Rebased after a long time of being abandon

Since the cogs folder has been removed, the error_handler and tag cogs had to be removed and transfer into their respective places in the exts folder.

52 files changed, 4741 insertions, 1320 deletions

diff --git a/tests/bot/cogs/sync/test_roles.py b/tests/bot/cogs/sync/test_roles.py
deleted file mode 100644
index 27ae27639..000000000
--- a/tests/bot/cogs/sync/test_roles.py
+++ /dev/null
@@ -1,126 +0,0 @@
-import unittest
-
-from bot.cogs.sync.syncers import Role, get_roles_for_sync
-
-
-class GetRolesForSyncTests(unittest.TestCase):
-    """Tests constructing the roles to synchronize with the site."""
-
-    def test_get_roles_for_sync_empty_return_for_equal_roles(self):
-        """No roles should be synced when no diff is found."""
-        api_roles = {Role(id=41, name='name', colour=33, permissions=0x8, position=1)}
-        guild_roles = {Role(id=41, name='name', colour=33, permissions=0x8, position=1)}
-
-        self.assertEqual(
-            get_roles_for_sync(guild_roles, api_roles),
-            (set(), set(), set())
-        )
-
-    def test_get_roles_for_sync_returns_roles_to_update_with_non_id_diff(self):
-        """Roles to be synced are returned when non-ID attributes differ."""
-        api_roles = {Role(id=41, name='old name', colour=35, permissions=0x8, position=1)}
-        guild_roles = {Role(id=41, name='new name', colour=33, permissions=0x8, position=2)}
-
-        self.assertEqual(
-            get_roles_for_sync(guild_roles, api_roles),
-            (set(), guild_roles, set())
-        )
-
-    def test_get_roles_only_returns_roles_that_require_update(self):
-        """Roles that require an update should be returned as the second tuple element."""
-        api_roles = {
-            Role(id=41, name='old name', colour=33, permissions=0x8, position=1),
-            Role(id=53, name='other role', colour=55, permissions=0, position=3)
-        }
-        guild_roles = {
-            Role(id=41, name='new name', colour=35, permissions=0x8, position=2),
-            Role(id=53, name='other role', colour=55, permissions=0, position=3)
-        }
-
-        self.assertEqual(
-            get_roles_for_sync(guild_roles, api_roles),
-            (
-                set(),
-                {Role(id=41, name='new name', colour=35, permissions=0x8, position=2)},
-                set(),
-            )
-        )
-
-    def test_get_roles_returns_new_roles_in_first_tuple_element(self):
-        """Newly created roles are returned as the first tuple element."""
-        api_roles = {
-            Role(id=41, name='name', colour=35, permissions=0x8, position=1),
-        }
-        guild_roles = {
-            Role(id=41, name='name', colour=35, permissions=0x8, position=1),
-            Role(id=53, name='other role', colour=55, permissions=0, position=2)
-        }
-
-        self.assertEqual(
-            get_roles_for_sync(guild_roles, api_roles),
-            (
-                {Role(id=53, name='other role', colour=55, permissions=0, position=2)},
-                set(),
-                set(),
-            )
-        )
-
-    def test_get_roles_returns_roles_to_update_and_new_roles(self):
-        """Newly created and updated roles should be returned together."""
-        api_roles = {
-            Role(id=41, name='old name', colour=35, permissions=0x8, position=1),
-        }
-        guild_roles = {
-            Role(id=41, name='new name', colour=40, permissions=0x16, position=2),
-            Role(id=53, name='other role', colour=55, permissions=0, position=3)
-        }
-
-        self.assertEqual(
-            get_roles_for_sync(guild_roles, api_roles),
-            (
-                {Role(id=53, name='other role', colour=55, permissions=0, position=3)},
-                {Role(id=41, name='new name', colour=40, permissions=0x16, position=2)},
-                set(),
-            )
-        )
-
-    def test_get_roles_returns_roles_to_delete(self):
-        """Roles to be deleted should be returned as the third tuple element."""
-        api_roles = {
-            Role(id=41, name='name', colour=35, permissions=0x8, position=1),
-            Role(id=61, name='to delete', colour=99, permissions=0x9, position=2),
-        }
-        guild_roles = {
-            Role(id=41, name='name', colour=35, permissions=0x8, position=1),
-        }
-
-        self.assertEqual(
-            get_roles_for_sync(guild_roles, api_roles),
-            (
-                set(),
-                set(),
-                {Role(id=61, name='to delete', colour=99, permissions=0x9, position=2)},
-            )
-        )
-
-    def test_get_roles_returns_roles_to_delete_update_and_new_roles(self):
-        """When roles were added, updated, and removed, all of them are returned properly."""
-        api_roles = {
-            Role(id=41, name='not changed', colour=35, permissions=0x8, position=1),
-            Role(id=61, name='to delete', colour=99, permissions=0x9, position=2),
-            Role(id=71, name='to update', colour=99, permissions=0x9, position=3),
-        }
-        guild_roles = {
-            Role(id=41, name='not changed', colour=35, permissions=0x8, position=1),
-            Role(id=81, name='to create', colour=99, permissions=0x9, position=4),
-            Role(id=71, name='updated', colour=101, permissions=0x5, position=3),
-        }
-
-        self.assertEqual(
-            get_roles_for_sync(guild_roles, api_roles),
-            (
-                {Role(id=81, name='to create', colour=99, permissions=0x9, position=4)},
-                {Role(id=71, name='updated', colour=101, permissions=0x5, position=3)},
-                {Role(id=61, name='to delete', colour=99, permissions=0x9, position=2)},
-            )
-        )
diff --git a/tests/bot/cogs/sync/test_users.py b/tests/bot/cogs/sync/test_users.py
deleted file mode 100644
index ccaf67490..000000000
--- a/tests/bot/cogs/sync/test_users.py
+++ /dev/null
@@ -1,84 +0,0 @@
-import unittest
-
-from bot.cogs.sync.syncers import User, get_users_for_sync
-
-
-def fake_user(**kwargs):
-    kwargs.setdefault('id', 43)
-    kwargs.setdefault('name', 'bob the test man')
-    kwargs.setdefault('discriminator', 1337)
-    kwargs.setdefault('avatar_hash', None)
-    kwargs.setdefault('roles', (666,))
-    kwargs.setdefault('in_guild', True)
-    return User(**kwargs)
-
-
-class GetUsersForSyncTests(unittest.TestCase):
-    """Tests constructing the users to synchronize with the site."""
-
-    def test_get_users_for_sync_returns_nothing_for_empty_params(self):
-        """When no users are given, none are returned."""
-        self.assertEqual(
-            get_users_for_sync({}, {}),
-            (set(), set())
-        )
-
-    def test_get_users_for_sync_returns_nothing_for_equal_users(self):
-        """When no users are updated, none are returned."""
-        api_users = {43: fake_user()}
-        guild_users = {43: fake_user()}
-
-        self.assertEqual(
-            get_users_for_sync(guild_users, api_users),
-            (set(), set())
-        )
-
-    def test_get_users_for_sync_returns_users_to_update_on_non_id_field_diff(self):
-        """When a non-ID-field differs, the user to update is returned."""
-        api_users = {43: fake_user()}
-        guild_users = {43: fake_user(name='new fancy name')}
-
-        self.assertEqual(
-            get_users_for_sync(guild_users, api_users),
-            (set(), {fake_user(name='new fancy name')})
-        )
-
-    def test_get_users_for_sync_returns_users_to_create_with_new_ids_on_guild(self):
-        """When new users join the guild, they are returned as the first tuple element."""
-        api_users = {43: fake_user()}
-        guild_users = {43: fake_user(), 63: fake_user(id=63)}
-
-        self.assertEqual(
-            get_users_for_sync(guild_users, api_users),
-            ({fake_user(id=63)}, set())
-        )
-
-    def test_get_users_for_sync_updates_in_guild_field_on_user_leave(self):
-        """When a user leaves the guild, the `in_guild` flag is updated to `False`."""
-        api_users = {43: fake_user(), 63: fake_user(id=63)}
-        guild_users = {43: fake_user()}
-
-        self.assertEqual(
-            get_users_for_sync(guild_users, api_users),
-            (set(), {fake_user(id=63, in_guild=False)})
-        )
-
-    def test_get_users_for_sync_updates_and_creates_users_as_needed(self):
-        """When one user left and another one was updated, both are returned."""
-        api_users = {43: fake_user()}
-        guild_users = {63: fake_user(id=63)}
-
-        self.assertEqual(
-            get_users_for_sync(guild_users, api_users),
-            ({fake_user(id=63)}, {fake_user(in_guild=False)})
-        )
-
-    def test_get_users_for_sync_does_not_duplicate_update_users(self):
-        """When the API knows a user the guild doesn't, nothing is performed."""
-        api_users = {43: fake_user(in_guild=False)}
-        guild_users = {}
-
-        self.assertEqual(
-            get_users_for_sync(guild_users, api_users),
-            (set(), set())
-        )
diff --git a/tests/bot/cogs/test_duck_pond.py b/tests/bot/cogs/test_duck_pond.py
deleted file mode 100644
index d07b2bce1..000000000
--- a/tests/bot/cogs/test_duck_pond.py
+++ /dev/null
@@ -1,584 +0,0 @@
-import asyncio
-import logging
-import typing
-import unittest
-from unittest.mock import MagicMock, patch
-
-import discord
-
-from bot import constants
-from bot.cogs import duck_pond
-from tests import base
-from tests import helpers
-
-MODULE_PATH = "bot.cogs.duck_pond"
-
-
-class DuckPondTests(base.LoggingTestCase):
-    """Tests for DuckPond functionality."""
-
-    @classmethod
-    def setUpClass(cls):
-        """Sets up the objects that only have to be initialized once."""
-        cls.nonstaff_member = helpers.MockMember(name="Non-staffer")
-
-        cls.staff_role = helpers.MockRole(name="Staff role", id=constants.STAFF_ROLES[0])
-        cls.staff_member = helpers.MockMember(name="staffer", roles=[cls.staff_role])
-
-        cls.checkmark_emoji = "\N{White Heavy Check Mark}"
-        cls.thumbs_up_emoji = "\N{Thumbs Up Sign}"
-        cls.unicode_duck_emoji = "\N{Duck}"
-        cls.duck_pond_emoji = helpers.MockPartialEmoji(id=constants.DuckPond.custom_emojis[0])
-        cls.non_duck_custom_emoji = helpers.MockPartialEmoji(id=123)
-
-    def setUp(self):
-        """Sets up the objects that need to be refreshed before each test."""
-        self.bot = helpers.MockBot(user=helpers.MockMember(id=46692))
-        self.cog = duck_pond.DuckPond(bot=self.bot)
-
-    def test_duck_pond_correctly_initializes(self):
-        """`__init__ should set `bot` and `webhook_id` attributes and schedule `fetch_webhook`."""
-        bot = helpers.MockBot()
-        cog = MagicMock()
-
-        duck_pond.DuckPond.__init__(cog, bot)
-
-        self.assertEqual(cog.bot, bot)
-        self.assertEqual(cog.webhook_id, constants.Webhooks.duck_pond)
-        bot.loop.create_loop.called_once_with(cog.fetch_webhook())
-
-    def test_fetch_webhook_succeeds_without_connectivity_issues(self):
-        """The `fetch_webhook` method waits until `READY` event and sets the `webhook` attribute."""
-        self.bot.fetch_webhook.return_value = "dummy webhook"
-        self.cog.webhook_id = 1
-
-        asyncio.run(self.cog.fetch_webhook())
-
-        self.bot.wait_until_ready.assert_called_once()
-        self.bot.fetch_webhook.assert_called_once_with(1)
-        self.assertEqual(self.cog.webhook, "dummy webhook")
-
-    def test_fetch_webhook_logs_when_unable_to_fetch_webhook(self):
-        """The `fetch_webhook` method should log an exception when it fails to fetch the webhook."""
-        self.bot.fetch_webhook.side_effect = discord.HTTPException(response=MagicMock(), message="Not found.")
-        self.cog.webhook_id = 1
-
-        log = logging.getLogger('bot.cogs.duck_pond')
-        with self.assertLogs(logger=log, level=logging.ERROR) as log_watcher:
-            asyncio.run(self.cog.fetch_webhook())
-
-        self.bot.wait_until_ready.assert_called_once()
-        self.bot.fetch_webhook.assert_called_once_with(1)
-
-        self.assertEqual(len(log_watcher.records), 1)
-
-        record = log_watcher.records[0]
-        self.assertEqual(record.levelno, logging.ERROR)
-
-    def test_is_staff_returns_correct_values_based_on_instance_passed(self):
-        """The `is_staff` method should return correct values based on the instance passed."""
-        test_cases = (
-            (helpers.MockUser(name="User instance"), False),
-            (helpers.MockMember(name="Member instance without staff role"), False),
-            (helpers.MockMember(name="Member instance with staff role", roles=[self.staff_role]), True)
-        )
-
-        for user, expected_return in test_cases:
-            actual_return = self.cog.is_staff(user)
-            with self.subTest(user_type=user.name, expected_return=expected_return, actual_return=actual_return):
-                self.assertEqual(expected_return, actual_return)
-
-    @helpers.async_test
-    async def test_has_green_checkmark_correctly_detects_presence_of_green_checkmark_emoji(self):
-        """The `has_green_checkmark` method should only return `True` if one is present."""
-        test_cases = (
-            (
-                "No reactions", helpers.MockMessage(), False
-            ),
-            (
-                "No green check mark reactions",
-                helpers.MockMessage(reactions=[
-                    helpers.MockReaction(emoji=self.unicode_duck_emoji, users=[self.bot.user]),
-                    helpers.MockReaction(emoji=self.thumbs_up_emoji, users=[self.bot.user])
-                ]),
-                False
-            ),
-            (
-                "Green check mark reaction, but not from our bot",
-                helpers.MockMessage(reactions=[
-                    helpers.MockReaction(emoji=self.unicode_duck_emoji, users=[self.bot.user]),
-                    helpers.MockReaction(emoji=self.checkmark_emoji, users=[self.staff_member])
-                ]),
-                False
-            ),
-            (
-                "Green check mark reaction, with one from the bot",
-                helpers.MockMessage(reactions=[
-                    helpers.MockReaction(emoji=self.unicode_duck_emoji, users=[self.bot.user]),
-                    helpers.MockReaction(emoji=self.checkmark_emoji, users=[self.staff_member, self.bot.user])
-                ]),
-                True
-            )
-        )
-
-        for description, message, expected_return in test_cases:
-            actual_return = await self.cog.has_green_checkmark(message)
-            with self.subTest(
-                test_case=description,
-                expected_return=expected_return,
-                actual_return=actual_return
-            ):
-                self.assertEqual(expected_return, actual_return)
-
-    def test_send_webhook_correctly_passes_on_arguments(self):
-        """The `send_webhook` method should pass the arguments to the webhook correctly."""
-        self.cog.webhook = helpers.MockAsyncWebhook()
-
-        content = "fake content"
-        username = "fake username"
-        avatar_url = "fake avatar_url"
-        embed = "fake embed"
-
-        asyncio.run(self.cog.send_webhook(content, username, avatar_url, embed))
-
-        self.cog.webhook.send.assert_called_once_with(
-            content=content,
-            username=username,
-            avatar_url=avatar_url,
-            embed=embed
-        )
-
-    def test_send_webhook_logs_when_sending_message_fails(self):
-        """The `send_webhook` method should catch a `discord.HTTPException` and log accordingly."""
-        self.cog.webhook = helpers.MockAsyncWebhook()
-        self.cog.webhook.send.side_effect = discord.HTTPException(response=MagicMock(), message="Something failed.")
-
-        log = logging.getLogger('bot.cogs.duck_pond')
-        with self.assertLogs(logger=log, level=logging.ERROR) as log_watcher:
-            asyncio.run(self.cog.send_webhook())
-
-        self.assertEqual(len(log_watcher.records), 1)
-
-        record = log_watcher.records[0]
-        self.assertEqual(record.levelno, logging.ERROR)
-
-    def _get_reaction(
-        self,
-        emoji: typing.Union[str, helpers.MockEmoji],
-        staff: int = 0,
-        nonstaff: int = 0
-    ) -> helpers.MockReaction:
-        staffers = [helpers.MockMember(roles=[self.staff_role]) for _ in range(staff)]
-        nonstaffers = [helpers.MockMember() for _ in range(nonstaff)]
-        return helpers.MockReaction(emoji=emoji, users=staffers + nonstaffers)
-
-    @helpers.async_test
-    async def test_count_ducks_correctly_counts_the_number_of_eligible_duck_emojis(self):
-        """The `count_ducks` method should return the number of unique staffers who gave a duck."""
-        test_cases = (
-            # Simple test cases
-            # A message without reactions should return 0
-            (
-                "No reactions",
-                helpers.MockMessage(),
-                0
-            ),
-            # A message with a non-duck reaction from a non-staffer should return 0
-            (
-                "Non-duck reaction from non-staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.thumbs_up_emoji, nonstaff=1)]),
-                0
-            ),
-            # A message with a non-duck reaction from a staffer should return 0
-            (
-                "Non-duck reaction from staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.non_duck_custom_emoji, staff=1)]),
-                0
-            ),
-            # A message with a non-duck reaction from a non-staffer and staffer should return 0
-            (
-                "Non-duck reaction from staffer + non-staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.thumbs_up_emoji, staff=1, nonstaff=1)]),
-                0
-            ),
-            # A message with a unicode duck reaction from a non-staffer should return 0
-            (
-                "Unicode Duck Reaction from non-staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.unicode_duck_emoji, nonstaff=1)]),
-                0
-            ),
-            # A message with a unicode duck reaction from a staffer should return 1
-            (
-                "Unicode Duck Reaction from staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.unicode_duck_emoji, staff=1)]),
-                1
-            ),
-            # A message with a unicode duck reaction from a non-staffer and staffer should return 1
-            (
-                "Unicode Duck Reaction from staffer + non-staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.unicode_duck_emoji, staff=1, nonstaff=1)]),
-                1
-            ),
-            # A message with a duckpond duck reaction from a non-staffer should return 0
-            (
-                "Duckpond Duck Reaction from non-staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.duck_pond_emoji, nonstaff=1)]),
-                0
-            ),
-            # A message with a duckpond duck reaction from a staffer should return 1
-            (
-                "Duckpond Duck Reaction from staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.duck_pond_emoji, staff=1)]),
-                1
-            ),
-            # A message with a duckpond duck reaction from a non-staffer and staffer should return 1
-            (
-                "Duckpond Duck Reaction from staffer + non-staffer",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.duck_pond_emoji, staff=1, nonstaff=1)]),
-                1
-            ),
-
-            # Complex test cases
-            # A message with duckpond duck reactions from 3 staffers and 2 non-staffers returns 3
-            (
-                "Duckpond Duck Reaction from 3 staffers + 2 non-staffers",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=self.duck_pond_emoji, staff=3, nonstaff=2)]),
-                3
-            ),
-            # A staffer with multiple duck reactions only counts once
-            (
-                "Two different duck reactions from the same staffer",
-                helpers.MockMessage(
-                    reactions=[
-                        helpers.MockReaction(emoji=self.duck_pond_emoji, users=[self.staff_member]),
-                        helpers.MockReaction(emoji=self.unicode_duck_emoji, users=[self.staff_member]),
-                    ]
-                ),
-                1
-            ),
-            # A non-string emoji does not count (to test the `isinstance(reaction.emoji, str)` elif)
-            (
-                "Reaction with non-Emoji/str emoij from 3 staffers + 2 non-staffers",
-                helpers.MockMessage(reactions=[self._get_reaction(emoji=100, staff=3, nonstaff=2)]),
-                0
-            ),
-            # We correctly sum when multiple reactions are provided.
-            (
-                "Duckpond Duck Reaction from 3 staffers + 2 non-staffers",
-                helpers.MockMessage(
-                    reactions=[
-                        self._get_reaction(emoji=self.duck_pond_emoji, staff=3, nonstaff=2),
-                        self._get_reaction(emoji=self.unicode_duck_emoji, staff=4, nonstaff=9),
-                    ]
-                ),
-                3 + 4
-            ),
-        )
-
-        for description, message, expected_count in test_cases:
-            actual_count = await self.cog.count_ducks(message)
-            with self.subTest(test_case=description, expected_count=expected_count, actual_count=actual_count):
-                self.assertEqual(expected_count, actual_count)
-
-    @helpers.async_test
-    async def test_relay_message_correctly_relays_content_and_attachments(self):
-        """The `relay_message` method should correctly relay message content and attachments."""
-        send_webhook_path = f"{MODULE_PATH}.DuckPond.send_webhook"
-        send_attachments_path = f"{MODULE_PATH}.send_attachments"
-
-        self.cog.webhook = helpers.MockAsyncWebhook()
-
-        test_values = (
-            (helpers.MockMessage(clean_content="", attachments=[]), False, False),
-            (helpers.MockMessage(clean_content="message", attachments=[]), True, False),
-            (helpers.MockMessage(clean_content="", attachments=["attachment"]), False, True),
-            (helpers.MockMessage(clean_content="message", attachments=["attachment"]), True, True),
-        )
-
-        for message, expect_webhook_call, expect_attachment_call in test_values:
-            with patch(send_webhook_path, new_callable=helpers.AsyncMock) as send_webhook:
-                with patch(send_attachments_path, new_callable=helpers.AsyncMock) as send_attachments:
-                    with self.subTest(clean_content=message.clean_content, attachments=message.attachments):
-                        await self.cog.relay_message(message)
-
-                        self.assertEqual(expect_webhook_call, send_webhook.called)
-                        self.assertEqual(expect_attachment_call, send_attachments.called)
-
-                        message.add_reaction.assert_called_once_with(self.checkmark_emoji)
-
-    @patch(f"{MODULE_PATH}.send_attachments", new_callable=helpers.AsyncMock)
-    @helpers.async_test
-    async def test_relay_message_handles_irretrievable_attachment_exceptions(self, send_attachments):
-        """The `relay_message` method should handle irretrievable attachments."""
-        message = helpers.MockMessage(clean_content="message", attachments=["attachment"])
-        side_effects = (discord.errors.Forbidden(MagicMock(), ""), discord.errors.NotFound(MagicMock(), ""))
-
-        self.cog.webhook = helpers.MockAsyncWebhook()
-        log = logging.getLogger("bot.cogs.duck_pond")
-
-        for side_effect in side_effects:
-            send_attachments.side_effect = side_effect
-            with patch(f"{MODULE_PATH}.DuckPond.send_webhook", new_callable=helpers.AsyncMock) as send_webhook:
-                with self.subTest(side_effect=type(side_effect).__name__):
-                    with self.assertNotLogs(logger=log, level=logging.ERROR):
-                        await self.cog.relay_message(message)
-
-                    self.assertEqual(send_webhook.call_count, 2)
-
-    @patch(f"{MODULE_PATH}.DuckPond.send_webhook", new_callable=helpers.AsyncMock)
-    @patch(f"{MODULE_PATH}.send_attachments", new_callable=helpers.AsyncMock)
-    @helpers.async_test
-    async def test_relay_message_handles_attachment_http_error(self, send_attachments, send_webhook):
-        """The `relay_message` method should handle irretrievable attachments."""
-        message = helpers.MockMessage(clean_content="message", attachments=["attachment"])
-
-        self.cog.webhook = helpers.MockAsyncWebhook()
-        log = logging.getLogger("bot.cogs.duck_pond")
-
-        side_effect = discord.HTTPException(MagicMock(), "")
-        send_attachments.side_effect = side_effect
-        with self.subTest(side_effect=type(side_effect).__name__):
-            with self.assertLogs(logger=log, level=logging.ERROR) as log_watcher:
-                await self.cog.relay_message(message)
-
-            send_webhook.assert_called_once_with(
-                content=message.clean_content,
-                username=message.author.display_name,
-                avatar_url=message.author.avatar_url
-            )
-
-            self.assertEqual(len(log_watcher.records), 1)
-
-            record = log_watcher.records[0]
-            self.assertEqual(record.levelno, logging.ERROR)
-
-    def _mock_payload(self, label: str, is_custom_emoji: bool, id_: int, emoji_name: str):
-        """Creates a mock `on_raw_reaction_add` payload with the specified emoji data."""
-        payload = MagicMock(name=label)
-        payload.emoji.is_custom_emoji.return_value = is_custom_emoji
-        payload.emoji.id = id_
-        payload.emoji.name = emoji_name
-        return payload
-
-    @helpers.async_test
-    async def test_payload_has_duckpond_emoji_correctly_detects_relevant_emojis(self):
-        """The `on_raw_reaction_add` event handler should ignore irrelevant emojis."""
-        test_values = (
-            # Custom Emojis
-            (
-                self._mock_payload(
-                    label="Custom Duckpond Emoji",
-                    is_custom_emoji=True,
-                    id_=constants.DuckPond.custom_emojis[0],
-                    emoji_name=""
-                ),
-                True
-            ),
-            (
-                self._mock_payload(
-                    label="Custom Non-Duckpond Emoji",
-                    is_custom_emoji=True,
-                    id_=123,
-                    emoji_name=""
-                ),
-                False
-            ),
-            # Unicode Emojis
-            (
-                self._mock_payload(
-                    label="Unicode Duck Emoji",
-                    is_custom_emoji=False,
-                    id_=1,
-                    emoji_name=self.unicode_duck_emoji
-                ),
-                True
-            ),
-            (
-                self._mock_payload(
-                    label="Unicode Non-Duck Emoji",
-                    is_custom_emoji=False,
-                    id_=1,
-                    emoji_name=self.thumbs_up_emoji
-                ),
-                False
-            ),
-        )
-
-        for payload, expected_return in test_values:
-            actual_return = self.cog._payload_has_duckpond_emoji(payload)
-            with self.subTest(case=payload._mock_name, expected_return=expected_return, actual_return=actual_return):
-                self.assertEqual(expected_return, actual_return)
-
-    @patch(f"{MODULE_PATH}.discord.utils.get")
-    @patch(f"{MODULE_PATH}.DuckPond._payload_has_duckpond_emoji", new=MagicMock(return_value=False))
-    def test_on_raw_reaction_add_returns_early_with_payload_without_duck_emoji(self, utils_get):
-        """The `on_raw_reaction_add` method should return early if the payload does not contain a duck emoji."""
-        self.assertIsNone(asyncio.run(self.cog.on_raw_reaction_add(payload=MagicMock())))
-
-        # Ensure we've returned before making an unnecessary API call in the lines of code after the emoji check
-        utils_get.assert_not_called()
-
-    def _raw_reaction_mocks(self, channel_id, message_id, user_id):
-        """Sets up mocks for tests of the `on_raw_reaction_add` event listener."""
-        channel = helpers.MockTextChannel(id=channel_id)
-        self.bot.get_all_channels.return_value = (channel,)
-
-        message = helpers.MockMessage(id=message_id)
-
-        channel.fetch_message.return_value = message
-
-        member = helpers.MockMember(id=user_id, roles=[self.staff_role])
-        message.guild.members = (member,)
-
-        payload = MagicMock(channel_id=channel_id, message_id=message_id, user_id=user_id)
-
-        return channel, message, member, payload
-
-    @helpers.async_test
-    async def test_on_raw_reaction_add_returns_for_bot_and_non_staff_members(self):
-        """The `on_raw_reaction_add` event handler should return for bot users or non-staff members."""
-        channel_id = 1234
-        message_id = 2345
-        user_id = 3456
-
-        channel, message, _, payload = self._raw_reaction_mocks(channel_id, message_id, user_id)
-
-        test_cases = (
-            ("non-staff member", helpers.MockMember(id=user_id)),
-            ("bot staff member", helpers.MockMember(id=user_id, roles=[self.staff_role], bot=True)),
-        )
-
-        payload.emoji = self.duck_pond_emoji
-
-        for description, member in test_cases:
-            message.guild.members = (member, )
-            with self.subTest(test_case=description), patch(f"{MODULE_PATH}.DuckPond.has_green_checkmark") as checkmark:
-                checkmark.side_effect = AssertionError(
-                    "Expected method to return before calling `self.has_green_checkmark`."
-                )
-                self.assertIsNone(await self.cog.on_raw_reaction_add(payload))
-
-                # Check that we did make it past the payload checks
-                channel.fetch_message.assert_called_once()
-                channel.fetch_message.reset_mock()
-
-    @patch(f"{MODULE_PATH}.DuckPond.is_staff")
-    @patch(f"{MODULE_PATH}.DuckPond.count_ducks", new_callable=helpers.AsyncMock)
-    def test_on_raw_reaction_add_returns_on_message_with_green_checkmark_placed_by_bot(self, count_ducks, is_staff):
-        """The `on_raw_reaction_add` event should return when the message has a green check mark placed by the bot."""
-        channel_id = 31415926535
-        message_id = 27182818284
-        user_id = 16180339887
-
-        channel, message, member, payload = self._raw_reaction_mocks(channel_id, message_id, user_id)
-
-        payload.emoji = helpers.MockPartialEmoji(name=self.unicode_duck_emoji)
-        payload.emoji.is_custom_emoji.return_value = False
-
-        message.reactions = [helpers.MockReaction(emoji=self.checkmark_emoji, users=[self.bot.user])]
-
-        is_staff.return_value = True
-        count_ducks.side_effect = AssertionError("Expected method to return before calling `self.count_ducks`")
-
-        self.assertIsNone(asyncio.run(self.cog.on_raw_reaction_add(payload)))
-
-        # Assert that we've made it past `self.is_staff`
-        is_staff.assert_called_once()
-
-    @helpers.async_test
-    async def test_on_raw_reaction_add_does_not_relay_below_duck_threshold(self):
-        """The `on_raw_reaction_add` listener should not relay messages or attachments below the duck threshold."""
-        test_cases = (
-            (constants.DuckPond.threshold - 1, False),
-            (constants.DuckPond.threshold, True),
-            (constants.DuckPond.threshold + 1, True),
-        )
-
-        channel, message, member, payload = self._raw_reaction_mocks(channel_id=3, message_id=4, user_id=5)
-
-        payload.emoji = self.duck_pond_emoji
-
-        for duck_count, should_relay in test_cases:
-            with patch(f"{MODULE_PATH}.DuckPond.relay_message", new_callable=helpers.AsyncMock) as relay_message:
-                with patch(f"{MODULE_PATH}.DuckPond.count_ducks", new_callable=helpers.AsyncMock) as count_ducks:
-                    count_ducks.return_value = duck_count
-                    with self.subTest(duck_count=duck_count, should_relay=should_relay):
-                        await self.cog.on_raw_reaction_add(payload)
-
-                        # Confirm that we've made it past counting
-                        count_ducks.assert_called_once()
-
-                        # Did we relay a message?
-                        has_relayed = relay_message.called
-                        self.assertEqual(has_relayed, should_relay)
-
-                        if should_relay:
-                            relay_message.assert_called_once_with(message)
-
-    @helpers.async_test
-    async def test_on_raw_reaction_remove_prevents_removal_of_green_checkmark_depending_on_the_duck_count(self):
-        """The `on_raw_reaction_remove` listener prevents removal of the check mark on messages with enough ducks."""
-        checkmark = helpers.MockPartialEmoji(name=self.checkmark_emoji)
-
-        message = helpers.MockMessage(id=1234)
-
-        channel = helpers.MockTextChannel(id=98765)
-        channel.fetch_message.return_value = message
-
-        self.bot.get_all_channels.return_value = (channel, )
-
-        payload = MagicMock(channel_id=channel.id, message_id=message.id, emoji=checkmark)
-
-        test_cases = (
-            (constants.DuckPond.threshold - 1, False),
-            (constants.DuckPond.threshold, True),
-            (constants.DuckPond.threshold + 1, True),
-        )
-        for duck_count, should_re_add_checkmark in test_cases:
-            with patch(f"{MODULE_PATH}.DuckPond.count_ducks", new_callable=helpers.AsyncMock) as count_ducks:
-                count_ducks.return_value = duck_count
-                with self.subTest(duck_count=duck_count, should_re_add_checkmark=should_re_add_checkmark):
-                    await self.cog.on_raw_reaction_remove(payload)
-
-                    # Check if we fetched the message
-                    channel.fetch_message.assert_called_once_with(message.id)
-
-                    # Check if we actually counted the number of ducks
-                    count_ducks.assert_called_once_with(message)
-
-                    has_re_added_checkmark = message.add_reaction.called
-                    self.assertEqual(should_re_add_checkmark, has_re_added_checkmark)
-
-                    if should_re_add_checkmark:
-                        message.add_reaction.assert_called_once_with(self.checkmark_emoji)
-                        message.add_reaction.reset_mock()
-
-                    # reset mocks
-                    channel.fetch_message.reset_mock()
-                    message.reset_mock()
-
-    def test_on_raw_reaction_remove_ignores_removal_of_non_checkmark_reactions(self):
-        """The `on_raw_reaction_remove` listener should ignore the removal of non-check mark emojis."""
-        channel = helpers.MockTextChannel(id=98765)
-
-        channel.fetch_message.side_effect = AssertionError(
-            "Expected method to return before calling `channel.fetch_message`"
-        )
-
-        self.bot.get_all_channels.return_value = (channel, )
-
-        payload = MagicMock(emoji=helpers.MockPartialEmoji(name=self.thumbs_up_emoji), channel_id=channel.id)
-
-        self.assertIsNone(asyncio.run(self.cog.on_raw_reaction_remove(payload)))
-
-        channel.fetch_message.assert_not_called()
-
-
-class DuckPondSetupTests(unittest.TestCase):
-    """Tests setup of the `DuckPond` cog."""
-
-    def test_setup(self):
-        """Setup of the extension should call add_cog."""
-        bot = helpers.MockBot()
-        duck_pond.setup(bot)
-        bot.add_cog.assert_called_once()
diff --git a/tests/bot/cogs/test_token_remover.py b/tests/bot/cogs/test_token_remover.py
deleted file mode 100644
index a54b839d7..000000000
--- a/tests/bot/cogs/test_token_remover.py
+++ /dev/null
@@ -1,131 +0,0 @@
-import asyncio
-import logging
-import unittest
-from unittest.mock import MagicMock
-
-from discord import Colour
-
-from bot.cogs.token_remover import (
-    DELETION_MESSAGE_TEMPLATE,
-    TokenRemover,
-    setup as setup_cog,
-)
-from bot.constants import Channels, Colours, Event, Icons
-from tests.helpers import AsyncMock, MockBot, MockMessage
-
-
-class TokenRemoverTests(unittest.TestCase):
-    """Tests the `TokenRemover` cog."""
-
-    def setUp(self):
-        """Adds the cog, a bot, and a message to the instance for usage in tests."""
-        self.bot = MockBot()
-        self.bot.get_cog.return_value = MagicMock()
-        self.bot.get_cog.return_value.send_log_message = AsyncMock()
-        self.cog = TokenRemover(bot=self.bot)
-
-        self.msg = MockMessage(id=555, content='')
-        self.msg.author.__str__ = MagicMock()
-        self.msg.author.__str__.return_value = 'lemon'
-        self.msg.author.bot = False
-        self.msg.author.avatar_url_as.return_value = 'picture-lemon.png'
-        self.msg.author.id = 42
-        self.msg.author.mention = '@lemon'
-        self.msg.channel.mention = "#lemonade-stand"
-
-    def test_is_valid_user_id_is_true_for_numeric_content(self):
-        """A string decoding to numeric characters is a valid user ID."""
-        # MTIz = base64(123)
-        self.assertTrue(TokenRemover.is_valid_user_id('MTIz'))
-
-    def test_is_valid_user_id_is_false_for_alphabetic_content(self):
-        """A string decoding to alphabetic characters is not a valid user ID."""
-        # YWJj = base64(abc)
-        self.assertFalse(TokenRemover.is_valid_user_id('YWJj'))
-
-    def test_is_valid_timestamp_is_true_for_valid_timestamps(self):
-        """A string decoding to a valid timestamp should be recognized as such."""
-        self.assertTrue(TokenRemover.is_valid_timestamp('DN9r_A'))
-
-    def test_is_valid_timestamp_is_false_for_invalid_values(self):
-        """A string not decoding to a valid timestamp should not be recognized as such."""
-        # MTIz = base64(123)
-        self.assertFalse(TokenRemover.is_valid_timestamp('MTIz'))
-
-    def test_mod_log_property(self):
-        """The `mod_log` property should ask the bot to return the `ModLog` cog."""
-        self.bot.get_cog.return_value = 'lemon'
-        self.assertEqual(self.cog.mod_log, self.bot.get_cog.return_value)
-        self.bot.get_cog.assert_called_once_with('ModLog')
-
-    def test_ignores_bot_messages(self):
-        """When the message event handler is called with a bot message, nothing is done."""
-        self.msg.author.bot = True
-        coroutine = self.cog.on_message(self.msg)
-        self.assertIsNone(asyncio.run(coroutine))
-
-    def test_ignores_messages_without_tokens(self):
-        """Messages without anything looking like a token are ignored."""
-        for content in ('', 'lemon wins'):
-            with self.subTest(content=content):
-                self.msg.content = content
-                coroutine = self.cog.on_message(self.msg)
-                self.assertIsNone(asyncio.run(coroutine))
-
-    def test_ignores_messages_with_invalid_tokens(self):
-        """Messages with values that are invalid tokens are ignored."""
-        for content in ('foo.bar.baz', 'x.y.'):
-            with self.subTest(content=content):
-                self.msg.content = content
-                coroutine = self.cog.on_message(self.msg)
-                self.assertIsNone(asyncio.run(coroutine))
-
-    def test_censors_valid_tokens(self):
-        """Valid tokens are censored."""
-        cases = (
-            # (content, censored_token)
-            ('MTIz.DN9R_A.xyz', 'MTIz.DN9R_A.xxx'),
-        )
-
-        for content, censored_token in cases:
-            with self.subTest(content=content, censored_token=censored_token):
-                self.msg.content = content
-                coroutine = self.cog.on_message(self.msg)
-                with self.assertLogs(logger='bot.cogs.token_remover', level=logging.DEBUG) as cm:
-                    self.assertIsNone(asyncio.run(coroutine))  # no return value
-
-                [line] = cm.output
-                log_message = (
-                    "Censored a seemingly valid token sent by "
-                    "lemon (`42`) in #lemonade-stand, "
-                    f"token was `{censored_token}`"
-                )
-                self.assertIn(log_message, line)
-
-                self.msg.delete.assert_called_once_with()
-                self.msg.channel.send.assert_called_once_with(
-                    DELETION_MESSAGE_TEMPLATE.format(mention='@lemon')
-                )
-                self.bot.get_cog.assert_called_with('ModLog')
-                self.msg.author.avatar_url_as.assert_called_once_with(static_format='png')
-
-                mod_log = self.bot.get_cog.return_value
-                mod_log.ignore.assert_called_once_with(Event.message_delete, self.msg.id)
-                mod_log.send_log_message.assert_called_once_with(
-                    icon_url=Icons.token_removed,
-                    colour=Colour(Colours.soft_red),
-                    title="Token removed!",
-                    text=log_message,
-                    thumbnail='picture-lemon.png',
-                    channel_id=Channels.mod_alerts
-                )
-
-
-class TokenRemoverSetupTests(unittest.TestCase):
-    """Tests setup of the `TokenRemover` cog."""
-
-    def test_setup(self):
-        """Setup of the extension should call add_cog."""
-        bot = MockBot()
-        setup_cog(bot)
-        bot.add_cog.assert_called_once()
diff --git a/tests/bot/cogs/__init__.py b/tests/bot/exts/__init__.py
index e69de29bb..e69de29bb 100644
--- a/tests/bot/cogs/__init__.py
+++ b/tests/bot/exts/__init__.py
diff --git a/tests/bot/cogs/sync/__init__.py b/tests/bot/exts/backend/__init__.py
index e69de29bb..e69de29bb 100644
--- a/tests/bot/cogs/sync/__init__.py
+++ b/tests/bot/exts/backend/__init__.py
diff --git a/tests/bot/patches/__init__.py b/tests/bot/exts/backend/sync/__init__.py
index e69de29bb..e69de29bb 100644
--- a/tests/bot/patches/__init__.py
+++ b/tests/bot/exts/backend/sync/__init__.py
diff --git a/tests/bot/exts/backend/sync/test_base.py b/tests/bot/exts/backend/sync/test_base.py
new file mode 100644
index 000000000..3ad9db9c3
--- /dev/null
+++ b/tests/bot/exts/backend/sync/test_base.py
@@ -0,0 +1,66 @@
+import unittest
+from unittest import mock
+
+
+from bot.api import ResponseCodeError
+from bot.exts.backend.sync._syncers import Syncer
+from tests import helpers
+
+
+class TestSyncer(Syncer):
+    """Syncer subclass with mocks for abstract methods for testing purposes."""
+
+    name = "test"
+    _get_diff = mock.AsyncMock()
+    _sync = mock.AsyncMock()
+
+
+class SyncerSyncTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for main function orchestrating the sync."""
+
+    def setUp(self):
+        patcher = mock.patch("bot.instance", new=helpers.MockBot(user=helpers.MockMember(bot=True)))
+        self.bot = patcher.start()
+        self.addCleanup(patcher.stop)
+
+        self.guild = helpers.MockGuild()
+
+        TestSyncer._get_diff.reset_mock(return_value=True, side_effect=True)
+        TestSyncer._sync.reset_mock(return_value=True, side_effect=True)
+
+        # Make sure `_get_diff` returns a MagicMock, not an AsyncMock
+        TestSyncer._get_diff.return_value = mock.MagicMock()
+
+    async def test_sync_message_edited(self):
+        """The message should be edited if one was sent, even if the sync has an API error."""
+        subtests = (
+            (None, None, False),
+            (helpers.MockMessage(), None, True),
+            (helpers.MockMessage(), ResponseCodeError(mock.MagicMock()), True),
+        )
+
+        for message, side_effect, should_edit in subtests:
+            with self.subTest(message=message, side_effect=side_effect, should_edit=should_edit):
+                TestSyncer._sync.side_effect = side_effect
+                ctx = helpers.MockContext()
+                ctx.send.return_value = message
+
+                await TestSyncer.sync(self.guild, ctx)
+
+                if should_edit:
+                    message.edit.assert_called_once()
+                    self.assertIn("content", message.edit.call_args[1])
+
+    async def test_sync_message_sent(self):
+        """If ctx is given, a new message should be sent."""
+        subtests = (
+            (None, None),
+            (helpers.MockContext(), helpers.MockMessage()),
+        )
+
+        for ctx, message in subtests:
+            with self.subTest(ctx=ctx, message=message):
+                await TestSyncer.sync(self.guild, ctx)
+
+                if ctx is not None:
+                    ctx.send.assert_called_once()
diff --git a/tests/bot/exts/backend/sync/test_cog.py b/tests/bot/exts/backend/sync/test_cog.py
new file mode 100644
index 000000000..22a07313e
--- /dev/null
+++ b/tests/bot/exts/backend/sync/test_cog.py
@@ -0,0 +1,414 @@
+import unittest
+from unittest import mock
+
+import discord
+
+from bot import constants
+from bot.api import ResponseCodeError
+from bot.exts.backend import sync
+from bot.exts.backend.sync._cog import Sync
+from bot.exts.backend.sync._syncers import Syncer
+from tests import helpers
+from tests.base import CommandTestCase
+
+
+class SyncExtensionTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for the sync extension."""
+
+    @staticmethod
+    def test_extension_setup():
+        """The Sync cog should be added."""
+        bot = helpers.MockBot()
+        sync.setup(bot)
+        bot.add_cog.assert_called_once()
+
+
+class SyncCogTestCase(unittest.IsolatedAsyncioTestCase):
+    """Base class for Sync cog tests. Sets up patches for syncers."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+
+        role_syncer_patcher = mock.patch(
+            "bot.exts.backend.sync._syncers.RoleSyncer",
+            autospec=Syncer,
+            spec_set=True
+        )
+        user_syncer_patcher = mock.patch(
+            "bot.exts.backend.sync._syncers.UserSyncer",
+            autospec=Syncer,
+            spec_set=True
+        )
+
+        self.RoleSyncer = role_syncer_patcher.start()
+        self.UserSyncer = user_syncer_patcher.start()
+
+        self.addCleanup(role_syncer_patcher.stop)
+        self.addCleanup(user_syncer_patcher.stop)
+
+        self.cog = Sync(self.bot)
+
+    @staticmethod
+    def response_error(status: int) -> ResponseCodeError:
+        """Fixture to return a ResponseCodeError with the given status code."""
+        response = mock.MagicMock()
+        response.status = status
+
+        return ResponseCodeError(response)
+
+
+class SyncCogTests(SyncCogTestCase):
+    """Tests for the Sync cog."""
+
+    @mock.patch.object(Sync, "sync_guild", new_callable=mock.MagicMock)
+    def test_sync_cog_init(self, sync_guild):
+        """Should instantiate syncers and run a sync for the guild."""
+        # Reset because a Sync cog was already instantiated in setUp.
+        self.RoleSyncer.reset_mock()
+        self.UserSyncer.reset_mock()
+        self.bot.loop.create_task = mock.MagicMock()
+
+        mock_sync_guild_coro = mock.MagicMock()
+        sync_guild.return_value = mock_sync_guild_coro
+
+        Sync(self.bot)
+
+        sync_guild.assert_called_once_with()
+        self.bot.loop.create_task.assert_called_once_with(mock_sync_guild_coro)
+
+    async def test_sync_cog_sync_guild(self):
+        """Roles and users should be synced only if a guild is successfully retrieved."""
+        for guild in (helpers.MockGuild(), None):
+            with self.subTest(guild=guild):
+                self.bot.reset_mock()
+                self.RoleSyncer.reset_mock()
+                self.UserSyncer.reset_mock()
+
+                self.bot.get_guild = mock.MagicMock(return_value=guild)
+
+                await self.cog.sync_guild()
+
+                self.bot.wait_until_guild_available.assert_called_once()
+                self.bot.get_guild.assert_called_once_with(constants.Guild.id)
+
+                if guild is None:
+                    self.RoleSyncer.sync.assert_not_called()
+                    self.UserSyncer.sync.assert_not_called()
+                else:
+                    self.RoleSyncer.sync.assert_called_once_with(guild)
+                    self.UserSyncer.sync.assert_called_once_with(guild)
+
+    async def patch_user_helper(self, side_effect: BaseException) -> None:
+        """Helper to set a side effect for bot.api_client.patch and then assert it is called."""
+        self.bot.api_client.patch.reset_mock(side_effect=True)
+        self.bot.api_client.patch.side_effect = side_effect
+
+        user_id, updated_information = 5, {"key": 123}
+        await self.cog.patch_user(user_id, updated_information)
+
+        self.bot.api_client.patch.assert_called_once_with(
+            f"bot/users/{user_id}",
+            json=updated_information,
+        )
+
+    async def test_sync_cog_patch_user(self):
+        """A PATCH request should be sent and 404 errors ignored."""
+        for side_effect in (None, self.response_error(404)):
+            with self.subTest(side_effect=side_effect):
+                await self.patch_user_helper(side_effect)
+
+    async def test_sync_cog_patch_user_non_404(self):
+        """A PATCH request should be sent and the error raised if it's not a 404."""
+        with self.assertRaises(ResponseCodeError):
+            await self.patch_user_helper(self.response_error(500))
+
+
+class SyncCogListenerTests(SyncCogTestCase):
+    """Tests for the listeners of the Sync cog."""
+
+    def setUp(self):
+        super().setUp()
+        self.cog.patch_user = mock.AsyncMock(spec_set=self.cog.patch_user)
+
+        self.guild_id_patcher = mock.patch("bot.exts.backend.sync._cog.constants.Guild.id", 5)
+        self.guild_id = self.guild_id_patcher.start()
+
+        self.guild = helpers.MockGuild(id=self.guild_id)
+        self.other_guild = helpers.MockGuild(id=0)
+
+    def tearDown(self):
+        self.guild_id_patcher.stop()
+
+    async def test_sync_cog_on_guild_role_create(self):
+        """A POST request should be sent with the new role's data."""
+        self.assertTrue(self.cog.on_guild_role_create.__cog_listener__)
+
+        role_data = {
+            "colour": 49,
+            "id": 777,
+            "name": "rolename",
+            "permissions": 8,
+            "position": 23,
+        }
+        role = helpers.MockRole(**role_data, guild=self.guild)
+        await self.cog.on_guild_role_create(role)
+
+        self.bot.api_client.post.assert_called_once_with("bot/roles", json=role_data)
+
+    async def test_sync_cog_on_guild_role_create_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        role = helpers.MockRole(guild=self.other_guild)
+        await self.cog.on_guild_role_create(role)
+        self.bot.api_client.post.assert_not_awaited()
+
+    async def test_sync_cog_on_guild_role_delete(self):
+        """A DELETE request should be sent."""
+        self.assertTrue(self.cog.on_guild_role_delete.__cog_listener__)
+
+        role = helpers.MockRole(id=99, guild=self.guild)
+        await self.cog.on_guild_role_delete(role)
+
+        self.bot.api_client.delete.assert_called_once_with("bot/roles/99")
+
+    async def test_sync_cog_on_guild_role_delete_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        role = helpers.MockRole(guild=self.other_guild)
+        await self.cog.on_guild_role_delete(role)
+        self.bot.api_client.delete.assert_not_awaited()
+
+    async def test_sync_cog_on_guild_role_update(self):
+        """A PUT request should be sent if the colour, name, permissions, or position changes."""
+        self.assertTrue(self.cog.on_guild_role_update.__cog_listener__)
+
+        role_data = {
+            "colour": 49,
+            "id": 777,
+            "name": "rolename",
+            "permissions": 8,
+            "position": 23,
+        }
+        subtests = (
+            (True, ("colour", "name", "permissions", "position")),
+            (False, ("hoist", "mentionable")),
+        )
+
+        for should_put, attributes in subtests:
+            for attribute in attributes:
+                with self.subTest(should_put=should_put, changed_attribute=attribute):
+                    self.bot.api_client.put.reset_mock()
+
+                    after_role_data = role_data.copy()
+                    after_role_data[attribute] = 876
+
+                    before_role = helpers.MockRole(**role_data, guild=self.guild)
+                    after_role = helpers.MockRole(**after_role_data, guild=self.guild)
+
+                    await self.cog.on_guild_role_update(before_role, after_role)
+
+                    if should_put:
+                        self.bot.api_client.put.assert_called_once_with(
+                            f"bot/roles/{after_role.id}",
+                            json=after_role_data
+                        )
+                    else:
+                        self.bot.api_client.put.assert_not_called()
+
+    async def test_sync_cog_on_guild_role_update_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        role = helpers.MockRole(guild=self.other_guild)
+        await self.cog.on_guild_role_update(role, role)
+        self.bot.api_client.put.assert_not_awaited()
+
+    async def test_sync_cog_on_member_remove(self):
+        """Member should be patched to set in_guild as False."""
+        self.assertTrue(self.cog.on_member_remove.__cog_listener__)
+
+        member = helpers.MockMember(guild=self.guild)
+        await self.cog.on_member_remove(member)
+
+        self.cog.patch_user.assert_called_once_with(
+            member.id,
+            json={"in_guild": False}
+        )
+
+    async def test_sync_cog_on_member_remove_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        member = helpers.MockMember(guild=self.other_guild)
+        await self.cog.on_member_remove(member)
+        self.cog.patch_user.assert_not_awaited()
+
+    async def test_sync_cog_on_member_update_roles(self):
+        """Members should be patched if their roles have changed."""
+        self.assertTrue(self.cog.on_member_update.__cog_listener__)
+
+        # Roles are intentionally unsorted.
+        before_roles = [helpers.MockRole(id=12), helpers.MockRole(id=30), helpers.MockRole(id=20)]
+        before_member = helpers.MockMember(roles=before_roles, guild=self.guild)
+        after_member = helpers.MockMember(roles=before_roles[1:], guild=self.guild)
+
+        await self.cog.on_member_update(before_member, after_member)
+
+        data = {"roles": sorted(role.id for role in after_member.roles)}
+        self.cog.patch_user.assert_called_once_with(after_member.id, json=data)
+
+    async def test_sync_cog_on_member_update_other(self):
+        """Members should not be patched if other attributes have changed."""
+        self.assertTrue(self.cog.on_member_update.__cog_listener__)
+
+        subtests = (
+            ("activities", discord.Game("Pong"), discord.Game("Frogger")),
+            ("nick", "old nick", "new nick"),
+            ("status", discord.Status.online, discord.Status.offline),
+        )
+
+        for attribute, old_value, new_value in subtests:
+            with self.subTest(attribute=attribute):
+                self.cog.patch_user.reset_mock()
+
+                before_member = helpers.MockMember(**{attribute: old_value}, guild=self.guild)
+                after_member = helpers.MockMember(**{attribute: new_value}, guild=self.guild)
+
+                await self.cog.on_member_update(before_member, after_member)
+
+                self.cog.patch_user.assert_not_called()
+
+    async def test_sync_cog_on_member_update_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        member = helpers.MockMember(guild=self.other_guild)
+        await self.cog.on_member_update(member, member)
+        self.cog.patch_user.assert_not_awaited()
+
+    async def test_sync_cog_on_user_update(self):
+        """A user should be patched only if the name, discriminator, or avatar changes."""
+        self.assertTrue(self.cog.on_user_update.__cog_listener__)
+
+        before_data = {
+            "name": "old name",
+            "discriminator": "1234",
+            "bot": False,
+        }
+
+        subtests = (
+            (True, "name", "name", "new name", "new name"),
+            (True, "discriminator", "discriminator", "8765", 8765),
+            (False, "bot", "bot", True, True),
+        )
+
+        for should_patch, attribute, api_field, value, api_value in subtests:
+            with self.subTest(attribute=attribute):
+                self.cog.patch_user.reset_mock()
+
+                after_data = before_data.copy()
+                after_data[attribute] = value
+                before_user = helpers.MockUser(**before_data)
+                after_user = helpers.MockUser(**after_data)
+
+                await self.cog.on_user_update(before_user, after_user)
+
+                if should_patch:
+                    self.cog.patch_user.assert_called_once()
+
+                    # Don't care if *all* keys are present; only the changed one is required
+                    call_args = self.cog.patch_user.call_args
+                    self.assertEqual(call_args.args[0], after_user.id)
+                    self.assertIn("json", call_args.kwargs)
+
+                    self.assertIn("ignore_404", call_args.kwargs)
+                    self.assertTrue(call_args.kwargs["ignore_404"])
+
+                    json = call_args.kwargs["json"]
+                    self.assertIn(api_field, json)
+                    self.assertEqual(json[api_field], api_value)
+                else:
+                    self.cog.patch_user.assert_not_called()
+
+    async def on_member_join_helper(self, side_effect: Exception) -> dict:
+        """
+        Helper to set `side_effect` for on_member_join and assert a PUT request was sent.
+
+        The request data for the mock member is returned. All exceptions will be re-raised.
+        """
+        member = helpers.MockMember(
+            discriminator="1234",
+            roles=[helpers.MockRole(id=22), helpers.MockRole(id=12)],
+            guild=self.guild,
+        )
+
+        data = {
+            "discriminator": int(member.discriminator),
+            "id": member.id,
+            "in_guild": True,
+            "name": member.name,
+            "roles": sorted(role.id for role in member.roles)
+        }
+
+        self.bot.api_client.put.reset_mock(side_effect=True)
+        self.bot.api_client.put.side_effect = side_effect
+
+        try:
+            await self.cog.on_member_join(member)
+        except Exception:
+            raise
+        finally:
+            self.bot.api_client.put.assert_called_once_with(
+                f"bot/users/{member.id}",
+                json=data
+            )
+
+        return data
+
+    async def test_sync_cog_on_member_join(self):
+        """Should PUT user's data or POST it if the user doesn't exist."""
+        for side_effect in (None, self.response_error(404)):
+            with self.subTest(side_effect=side_effect):
+                self.bot.api_client.post.reset_mock()
+                data = await self.on_member_join_helper(side_effect)
+
+                if side_effect:
+                    self.bot.api_client.post.assert_called_once_with("bot/users", json=data)
+                else:
+                    self.bot.api_client.post.assert_not_called()
+
+    async def test_sync_cog_on_member_join_non_404(self):
+        """ResponseCodeError should be re-raised if status code isn't a 404."""
+        with self.assertRaises(ResponseCodeError):
+            await self.on_member_join_helper(self.response_error(500))
+
+        self.bot.api_client.post.assert_not_called()
+
+    async def test_sync_cog_on_member_join_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        member = helpers.MockMember(guild=self.other_guild)
+        await self.cog.on_member_join(member)
+        self.bot.api_client.post.assert_not_awaited()
+        self.bot.api_client.put.assert_not_awaited()
+
+
+class SyncCogCommandTests(SyncCogTestCase, CommandTestCase):
+    """Tests for the commands in the Sync cog."""
+
+    async def test_sync_roles_command(self):
+        """sync() should be called on the RoleSyncer."""
+        ctx = helpers.MockContext()
+        await self.cog.sync_roles_command(self.cog, ctx)
+
+        self.RoleSyncer.sync.assert_called_once_with(ctx.guild, ctx)
+
+    async def test_sync_users_command(self):
+        """sync() should be called on the UserSyncer."""
+        ctx = helpers.MockContext()
+        await self.cog.sync_users_command(self.cog, ctx)
+
+        self.UserSyncer.sync.assert_called_once_with(ctx.guild, ctx)
+
+    async def test_commands_require_admin(self):
+        """The sync commands should only run if the author has the administrator permission."""
+        cmds = (
+            self.cog.sync_group,
+            self.cog.sync_roles_command,
+            self.cog.sync_users_command,
+        )
+
+        for cmd in cmds:
+            with self.subTest(cmd=cmd):
+                await self.assertHasPermissionsCheck(cmd, {"administrator": True})
diff --git a/tests/bot/exts/backend/sync/test_roles.py b/tests/bot/exts/backend/sync/test_roles.py
new file mode 100644
index 000000000..541074336
--- /dev/null
+++ b/tests/bot/exts/backend/sync/test_roles.py
@@ -0,0 +1,159 @@
+import unittest
+from unittest import mock
+
+import discord
+
+from bot.exts.backend.sync._syncers import RoleSyncer, _Diff, _Role
+from tests import helpers
+
+
+def fake_role(**kwargs):
+    """Fixture to return a dictionary representing a role with default values set."""
+    kwargs.setdefault("id", 9)
+    kwargs.setdefault("name", "fake role")
+    kwargs.setdefault("colour", 7)
+    kwargs.setdefault("permissions", 0)
+    kwargs.setdefault("position", 55)
+
+    return kwargs
+
+
+class RoleSyncerDiffTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for determining differences between roles in the DB and roles in the Guild cache."""
+
+    def setUp(self):
+        patcher = mock.patch("bot.instance", new=helpers.MockBot())
+        self.bot = patcher.start()
+        self.addCleanup(patcher.stop)
+
+    @staticmethod
+    def get_guild(*roles):
+        """Fixture to return a guild object with the given roles."""
+        guild = helpers.MockGuild()
+        guild.roles = []
+
+        for role in roles:
+            mock_role = helpers.MockRole(**role)
+            mock_role.colour = discord.Colour(role["colour"])
+            mock_role.permissions = discord.Permissions(role["permissions"])
+            guild.roles.append(mock_role)
+
+        return guild
+
+    async def test_empty_diff_for_identical_roles(self):
+        """No differences should be found if the roles in the guild and DB are identical."""
+        self.bot.api_client.get.return_value = [fake_role()]
+        guild = self.get_guild(fake_role())
+
+        actual_diff = await RoleSyncer._get_diff(guild)
+        expected_diff = (set(), set(), set())
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_diff_for_updated_roles(self):
+        """Only updated roles should be added to the 'updated' set of the diff."""
+        updated_role = fake_role(id=41, name="new")
+
+        self.bot.api_client.get.return_value = [fake_role(id=41, name="old"), fake_role()]
+        guild = self.get_guild(updated_role, fake_role())
+
+        actual_diff = await RoleSyncer._get_diff(guild)
+        expected_diff = (set(), {_Role(**updated_role)}, set())
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_diff_for_new_roles(self):
+        """Only new roles should be added to the 'created' set of the diff."""
+        new_role = fake_role(id=41, name="new")
+
+        self.bot.api_client.get.return_value = [fake_role()]
+        guild = self.get_guild(fake_role(), new_role)
+
+        actual_diff = await RoleSyncer._get_diff(guild)
+        expected_diff = ({_Role(**new_role)}, set(), set())
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_diff_for_deleted_roles(self):
+        """Only deleted roles should be added to the 'deleted' set of the diff."""
+        deleted_role = fake_role(id=61, name="deleted")
+
+        self.bot.api_client.get.return_value = [fake_role(), deleted_role]
+        guild = self.get_guild(fake_role())
+
+        actual_diff = await RoleSyncer._get_diff(guild)
+        expected_diff = (set(), set(), {_Role(**deleted_role)})
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_diff_for_new_updated_and_deleted_roles(self):
+        """When roles are added, updated, and removed, all of them are returned properly."""
+        new = fake_role(id=41, name="new")
+        updated = fake_role(id=71, name="updated")
+        deleted = fake_role(id=61, name="deleted")
+
+        self.bot.api_client.get.return_value = [
+            fake_role(),
+            fake_role(id=71, name="updated name"),
+            deleted,
+        ]
+        guild = self.get_guild(fake_role(), new, updated)
+
+        actual_diff = await RoleSyncer._get_diff(guild)
+        expected_diff = ({_Role(**new)}, {_Role(**updated)}, {_Role(**deleted)})
+
+        self.assertEqual(actual_diff, expected_diff)
+
+
+class RoleSyncerSyncTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for the API requests that sync roles."""
+
+    def setUp(self):
+        patcher = mock.patch("bot.instance", new=helpers.MockBot())
+        self.bot = patcher.start()
+        self.addCleanup(patcher.stop)
+
+    async def test_sync_created_roles(self):
+        """Only POST requests should be made with the correct payload."""
+        roles = [fake_role(id=111), fake_role(id=222)]
+
+        role_tuples = {_Role(**role) for role in roles}
+        diff = _Diff(role_tuples, set(), set())
+        await RoleSyncer._sync(diff)
+
+        calls = [mock.call("bot/roles", json=role) for role in roles]
+        self.bot.api_client.post.assert_has_calls(calls, any_order=True)
+        self.assertEqual(self.bot.api_client.post.call_count, len(roles))
+
+        self.bot.api_client.put.assert_not_called()
+        self.bot.api_client.delete.assert_not_called()
+
+    async def test_sync_updated_roles(self):
+        """Only PUT requests should be made with the correct payload."""
+        roles = [fake_role(id=111), fake_role(id=222)]
+
+        role_tuples = {_Role(**role) for role in roles}
+        diff = _Diff(set(), role_tuples, set())
+        await RoleSyncer._sync(diff)
+
+        calls = [mock.call(f"bot/roles/{role['id']}", json=role) for role in roles]
+        self.bot.api_client.put.assert_has_calls(calls, any_order=True)
+        self.assertEqual(self.bot.api_client.put.call_count, len(roles))
+
+        self.bot.api_client.post.assert_not_called()
+        self.bot.api_client.delete.assert_not_called()
+
+    async def test_sync_deleted_roles(self):
+        """Only DELETE requests should be made with the correct payload."""
+        roles = [fake_role(id=111), fake_role(id=222)]
+
+        role_tuples = {_Role(**role) for role in roles}
+        diff = _Diff(set(), set(), role_tuples)
+        await RoleSyncer._sync(diff)
+
+        calls = [mock.call(f"bot/roles/{role['id']}") for role in roles]
+        self.bot.api_client.delete.assert_has_calls(calls, any_order=True)
+        self.assertEqual(self.bot.api_client.delete.call_count, len(roles))
+
+        self.bot.api_client.post.assert_not_called()
+        self.bot.api_client.put.assert_not_called()
diff --git a/tests/bot/exts/backend/sync/test_users.py b/tests/bot/exts/backend/sync/test_users.py
new file mode 100644
index 000000000..61673e1bb
--- /dev/null
+++ b/tests/bot/exts/backend/sync/test_users.py
@@ -0,0 +1,217 @@
+import unittest
+from unittest import mock
+
+from bot.exts.backend.sync._syncers import UserSyncer, _Diff
+from tests import helpers
+
+
+def fake_user(**kwargs):
+    """Fixture to return a dictionary representing a user with default values set."""
+    kwargs.setdefault("id", 43)
+    kwargs.setdefault("name", "bob the test man")
+    kwargs.setdefault("discriminator", 1337)
+    kwargs.setdefault("roles", [666])
+    kwargs.setdefault("in_guild", True)
+
+    return kwargs
+
+
+class UserSyncerDiffTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for determining differences between users in the DB and users in the Guild cache."""
+
+    def setUp(self):
+        patcher = mock.patch("bot.instance", new=helpers.MockBot())
+        self.bot = patcher.start()
+        self.addCleanup(patcher.stop)
+
+    @staticmethod
+    def get_guild(*members):
+        """Fixture to return a guild object with the given members."""
+        guild = helpers.MockGuild()
+        guild.members = []
+
+        for member in members:
+            member = member.copy()
+            del member["in_guild"]
+
+            mock_member = helpers.MockMember(**member)
+            mock_member.roles = [helpers.MockRole(id=role_id) for role_id in member["roles"]]
+
+            guild.members.append(mock_member)
+
+        return guild
+
+    @staticmethod
+    def get_mock_member(member: dict):
+        member = member.copy()
+        del member["in_guild"]
+        mock_member = helpers.MockMember(**member)
+        mock_member.roles = [helpers.MockRole(id=role_id) for role_id in member["roles"]]
+        return mock_member
+
+    async def test_empty_diff_for_no_users(self):
+        """When no users are given, an empty diff should be returned."""
+        self.bot.api_client.get.return_value = {
+            "count": 3,
+            "next_page_no": None,
+            "previous_page_no": None,
+            "results": []
+        }
+        guild = self.get_guild()
+
+        actual_diff = await UserSyncer._get_diff(guild)
+        expected_diff = ([], [], None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_empty_diff_for_identical_users(self):
+        """No differences should be found if the users in the guild and DB are identical."""
+        self.bot.api_client.get.return_value = {
+            "count": 3,
+            "next_page_no": None,
+            "previous_page_no": None,
+            "results": [fake_user()]
+        }
+        guild = self.get_guild(fake_user())
+
+        guild.get_member.return_value = self.get_mock_member(fake_user())
+        actual_diff = await UserSyncer._get_diff(guild)
+        expected_diff = ([], [], None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_diff_for_updated_users(self):
+        """Only updated users should be added to the 'updated' set of the diff."""
+        updated_user = fake_user(id=99, name="new")
+
+        self.bot.api_client.get.return_value = {
+            "count": 3,
+            "next_page_no": None,
+            "previous_page_no": None,
+            "results": [fake_user(id=99, name="old"), fake_user()]
+        }
+        guild = self.get_guild(updated_user, fake_user())
+        guild.get_member.side_effect = [
+            self.get_mock_member(updated_user),
+            self.get_mock_member(fake_user())
+        ]
+
+        actual_diff = await UserSyncer._get_diff(guild)
+        expected_diff = ([], [{"id": 99, "name": "new"}], None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_diff_for_new_users(self):
+        """Only new users should be added to the 'created' list of the diff."""
+        new_user = fake_user(id=99, name="new")
+
+        self.bot.api_client.get.return_value = {
+            "count": 3,
+            "next_page_no": None,
+            "previous_page_no": None,
+            "results": [fake_user()]
+        }
+        guild = self.get_guild(fake_user(), new_user)
+        guild.get_member.side_effect = [
+            self.get_mock_member(fake_user()),
+            self.get_mock_member(new_user)
+        ]
+        actual_diff = await UserSyncer._get_diff(guild)
+        expected_diff = ([new_user], [], None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_diff_sets_in_guild_false_for_leaving_users(self):
+        """When a user leaves the guild, the `in_guild` flag is updated to `False`."""
+        self.bot.api_client.get.return_value = {
+            "count": 3,
+            "next_page_no": None,
+            "previous_page_no": None,
+            "results": [fake_user(), fake_user(id=63)]
+        }
+        guild = self.get_guild(fake_user())
+        guild.get_member.side_effect = [
+            self.get_mock_member(fake_user()),
+            None
+        ]
+
+        actual_diff = await UserSyncer._get_diff(guild)
+        expected_diff = ([], [{"id": 63, "in_guild": False}], None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_diff_for_new_updated_and_leaving_users(self):
+        """When users are added, updated, and removed, all of them are returned properly."""
+        new_user = fake_user(id=99, name="new")
+
+        updated_user = fake_user(id=55, name="updated")
+
+        self.bot.api_client.get.return_value = {
+            "count": 3,
+            "next_page_no": None,
+            "previous_page_no": None,
+            "results": [fake_user(), fake_user(id=55), fake_user(id=63)]
+        }
+        guild = self.get_guild(fake_user(), new_user, updated_user)
+        guild.get_member.side_effect = [
+            self.get_mock_member(fake_user()),
+            self.get_mock_member(updated_user),
+            None
+        ]
+
+        actual_diff = await UserSyncer._get_diff(guild)
+        expected_diff = ([new_user], [{"id": 55, "name": "updated"}, {"id": 63, "in_guild": False}], None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    async def test_empty_diff_for_db_users_not_in_guild(self):
+        """When the DB knows a user, but the guild doesn't, no difference is found."""
+        self.bot.api_client.get.return_value = {
+            "count": 3,
+            "next_page_no": None,
+            "previous_page_no": None,
+            "results": [fake_user(), fake_user(id=63, in_guild=False)]
+        }
+        guild = self.get_guild(fake_user())
+        guild.get_member.side_effect = [
+            self.get_mock_member(fake_user()),
+            None
+        ]
+
+        actual_diff = await UserSyncer._get_diff(guild)
+        expected_diff = ([], [], None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+
+class UserSyncerSyncTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for the API requests that sync users."""
+
+    def setUp(self):
+        patcher = mock.patch("bot.instance", new=helpers.MockBot())
+        self.bot = patcher.start()
+        self.addCleanup(patcher.stop)
+
+    async def test_sync_created_users(self):
+        """Only POST requests should be made with the correct payload."""
+        users = [fake_user(id=111), fake_user(id=222)]
+
+        diff = _Diff(users, [], None)
+        await UserSyncer._sync(diff)
+
+        self.bot.api_client.post.assert_called_once_with("bot/users", json=diff.created)
+
+        self.bot.api_client.put.assert_not_called()
+        self.bot.api_client.delete.assert_not_called()
+
+    async def test_sync_updated_users(self):
+        """Only PUT requests should be made with the correct payload."""
+        users = [fake_user(id=111), fake_user(id=222)]
+
+        diff = _Diff([], users, None)
+        await UserSyncer._sync(diff)
+
+        self.bot.api_client.patch.assert_called_once_with("bot/users/bulk_patch", json=diff.updated)
+
+        self.bot.api_client.post.assert_not_called()
+        self.bot.api_client.delete.assert_not_called()
diff --git a/tests/bot/exts/backend/test_logging.py b/tests/bot/exts/backend/test_logging.py
new file mode 100644
index 000000000..466f207d9
--- /dev/null
+++ b/tests/bot/exts/backend/test_logging.py
@@ -0,0 +1,32 @@
+import unittest
+from unittest.mock import patch
+
+from bot import constants
+from bot.exts.backend.logging import Logging
+from tests.helpers import MockBot, MockTextChannel
+
+
+class LoggingTests(unittest.IsolatedAsyncioTestCase):
+    """Test cases for connected login."""
+
+    def setUp(self):
+        self.bot = MockBot()
+        self.cog = Logging(self.bot)
+        self.dev_log = MockTextChannel(id=1234, name="dev-log")
+
+    @patch("bot.exts.backend.logging.DEBUG_MODE", False)
+    async def test_debug_mode_false(self):
+        """Should send connected message to dev-log."""
+        self.bot.get_channel.return_value = self.dev_log
+
+        await self.cog.startup_greeting()
+        self.bot.wait_until_guild_available.assert_awaited_once_with()
+        self.bot.get_channel.assert_called_once_with(constants.Channels.dev_log)
+        self.dev_log.send.assert_awaited_once()
+
+    @patch("bot.exts.backend.logging.DEBUG_MODE", True)
+    async def test_debug_mode_true(self):
+        """Should not send anything to dev-log."""
+        await self.cog.startup_greeting()
+        self.bot.wait_until_guild_available.assert_awaited_once_with()
+        self.bot.get_channel.assert_not_called()
diff --git a/tests/bot/exts/filters/__init__.py b/tests/bot/exts/filters/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/bot/exts/filters/__init__.py
diff --git a/tests/bot/exts/filters/test_antimalware.py b/tests/bot/exts/filters/test_antimalware.py
new file mode 100644
index 000000000..3393c6cdc
--- /dev/null
+++ b/tests/bot/exts/filters/test_antimalware.py
@@ -0,0 +1,187 @@
+import unittest
+from unittest.mock import AsyncMock, Mock
+
+from discord import NotFound
+
+from bot.constants import Channels, STAFF_ROLES
+from bot.exts.filters import antimalware
+from tests.helpers import MockAttachment, MockBot, MockMessage, MockRole
+
+
+class AntiMalwareCogTests(unittest.IsolatedAsyncioTestCase):
+    """Test the AntiMalware cog."""
+
+    def setUp(self):
+        """Sets up fresh objects for each test."""
+        self.bot = MockBot()
+        self.bot.filter_list_cache = {
+            "FILE_FORMAT.True": {
+                ".first": {},
+                ".second": {},
+                ".third": {},
+            }
+        }
+        self.cog = antimalware.AntiMalware(self.bot)
+        self.message = MockMessage()
+        self.message.webhook_id = None
+        self.message.author.bot = None
+        self.whitelist = [".first", ".second", ".third"]
+
+    async def test_message_with_allowed_attachment(self):
+        """Messages with allowed extensions should not be deleted"""
+        attachment = MockAttachment(filename="python.first")
+        self.message.attachments = [attachment]
+
+        await self.cog.on_message(self.message)
+        self.message.delete.assert_not_called()
+
+    async def test_message_without_attachment(self):
+        """Messages without attachments should result in no action."""
+        await self.cog.on_message(self.message)
+        self.message.delete.assert_not_called()
+
+    async def test_direct_message_with_attachment(self):
+        """Direct messages should have no action taken."""
+        attachment = MockAttachment(filename="python.disallowed")
+        self.message.attachments = [attachment]
+        self.message.guild = None
+
+        await self.cog.on_message(self.message)
+
+        self.message.delete.assert_not_called()
+
+    async def test_webhook_message_with_illegal_extension(self):
+        """A webhook message containing an illegal extension should be ignored."""
+        attachment = MockAttachment(filename="python.disallowed")
+        self.message.webhook_id = 697140105563078727
+        self.message.attachments = [attachment]
+
+        await self.cog.on_message(self.message)
+
+        self.message.delete.assert_not_called()
+
+    async def test_bot_message_with_illegal_extension(self):
+        """A bot message containing an illegal extension should be ignored."""
+        attachment = MockAttachment(filename="python.disallowed")
+        self.message.author.bot = 409107086526644234
+        self.message.attachments = [attachment]
+
+        await self.cog.on_message(self.message)
+
+        self.message.delete.assert_not_called()
+
+    async def test_message_with_illegal_extension_gets_deleted(self):
+        """A message containing an illegal extension should send an embed."""
+        attachment = MockAttachment(filename="python.disallowed")
+        self.message.attachments = [attachment]
+
+        await self.cog.on_message(self.message)
+
+        self.message.delete.assert_called_once()
+
+    async def test_message_send_by_staff(self):
+        """A message send by a member of staff should be ignored."""
+        staff_role = MockRole(id=STAFF_ROLES[0])
+        self.message.author.roles.append(staff_role)
+        attachment = MockAttachment(filename="python.disallowed")
+        self.message.attachments = [attachment]
+
+        await self.cog.on_message(self.message)
+
+        self.message.delete.assert_not_called()
+
+    async def test_python_file_redirect_embed_description(self):
+        """A message containing a .py file should result in an embed redirecting the user to our paste site"""
+        attachment = MockAttachment(filename="python.py")
+        self.message.attachments = [attachment]
+        self.message.channel.send = AsyncMock()
+
+        await self.cog.on_message(self.message)
+        self.message.channel.send.assert_called_once()
+        args, kwargs = self.message.channel.send.call_args
+        embed = kwargs.pop("embed")
+
+        self.assertEqual(embed.description, antimalware.PY_EMBED_DESCRIPTION)
+
+    async def test_txt_file_redirect_embed_description(self):
+        """A message containing a .txt file should result in the correct embed."""
+        attachment = MockAttachment(filename="python.txt")
+        self.message.attachments = [attachment]
+        self.message.channel.send = AsyncMock()
+        antimalware.TXT_EMBED_DESCRIPTION = Mock()
+        antimalware.TXT_EMBED_DESCRIPTION.format.return_value = "test"
+
+        await self.cog.on_message(self.message)
+        self.message.channel.send.assert_called_once()
+        args, kwargs = self.message.channel.send.call_args
+        embed = kwargs.pop("embed")
+        cmd_channel = self.bot.get_channel(Channels.bot_commands)
+
+        self.assertEqual(embed.description, antimalware.TXT_EMBED_DESCRIPTION.format.return_value)
+        antimalware.TXT_EMBED_DESCRIPTION.format.assert_called_with(cmd_channel_mention=cmd_channel.mention)
+
+    async def test_other_disallowed_extension_embed_description(self):
+        """Test the description for a non .py/.txt disallowed extension."""
+        attachment = MockAttachment(filename="python.disallowed")
+        self.message.attachments = [attachment]
+        self.message.channel.send = AsyncMock()
+        antimalware.DISALLOWED_EMBED_DESCRIPTION = Mock()
+        antimalware.DISALLOWED_EMBED_DESCRIPTION.format.return_value = "test"
+
+        await self.cog.on_message(self.message)
+        self.message.channel.send.assert_called_once()
+        args, kwargs = self.message.channel.send.call_args
+        embed = kwargs.pop("embed")
+        meta_channel = self.bot.get_channel(Channels.meta)
+
+        self.assertEqual(embed.description, antimalware.DISALLOWED_EMBED_DESCRIPTION.format.return_value)
+        antimalware.DISALLOWED_EMBED_DESCRIPTION.format.assert_called_with(
+            joined_whitelist=", ".join(self.whitelist),
+            blocked_extensions_str=".disallowed",
+            meta_channel_mention=meta_channel.mention
+        )
+
+    async def test_removing_deleted_message_logs(self):
+        """Removing an already deleted message logs the correct message"""
+        attachment = MockAttachment(filename="python.disallowed")
+        self.message.attachments = [attachment]
+        self.message.delete = AsyncMock(side_effect=NotFound(response=Mock(status=""), message=""))
+
+        with self.assertLogs(logger=antimalware.log, level="INFO"):
+            await self.cog.on_message(self.message)
+        self.message.delete.assert_called_once()
+
+    async def test_message_with_illegal_attachment_logs(self):
+        """Deleting a message with an illegal attachment should result in a log."""
+        attachment = MockAttachment(filename="python.disallowed")
+        self.message.attachments = [attachment]
+
+        with self.assertLogs(logger=antimalware.log, level="INFO"):
+            await self.cog.on_message(self.message)
+
+    async def test_get_disallowed_extensions(self):
+        """The return value should include all non-whitelisted extensions."""
+        test_values = (
+            ([], []),
+            (self.whitelist, []),
+            ([".first"], []),
+            ([".first", ".disallowed"], [".disallowed"]),
+            ([".disallowed"], [".disallowed"]),
+            ([".disallowed", ".illegal"], [".disallowed", ".illegal"]),
+        )
+
+        for extensions, expected_disallowed_extensions in test_values:
+            with self.subTest(extensions=extensions, expected_disallowed_extensions=expected_disallowed_extensions):
+                self.message.attachments = [MockAttachment(filename=f"filename{extension}") for extension in extensions]
+                disallowed_extensions = self.cog._get_disallowed_extensions(self.message)
+                self.assertCountEqual(disallowed_extensions, expected_disallowed_extensions)
+
+
+class AntiMalwareSetupTests(unittest.TestCase):
+    """Tests setup of the `AntiMalware` cog."""
+
+    def test_setup(self):
+        """Setup of the extension should call add_cog."""
+        bot = MockBot()
+        antimalware.setup(bot)
+        bot.add_cog.assert_called_once()
diff --git a/tests/bot/cogs/test_antispam.py b/tests/bot/exts/filters/test_antispam.py
index ce5472c71..6a0e4fded 100644
--- a/tests/bot/cogs/test_antispam.py
+++ b/tests/bot/exts/filters/test_antispam.py
@@ -1,6 +1,6 @@
 import unittest
 
-from bot.cogs import antispam
+from bot.exts.filters import antispam
 
 
 class AntispamConfigurationValidationTests(unittest.TestCase):
diff --git a/tests/bot/cogs/test_security.py b/tests/bot/exts/filters/test_security.py
index 9d1a62f7e..c0c3baa42 100644
--- a/tests/bot/cogs/test_security.py
+++ b/tests/bot/exts/filters/test_security.py
@@ -3,7 +3,7 @@ from unittest.mock import MagicMock
 
 from discord.ext.commands import NoPrivateMessage
 
-from bot.cogs import security
+from bot.exts.filters import security
 from tests.helpers import MockBot, MockContext
 
 
diff --git a/tests/bot/exts/filters/test_token_remover.py b/tests/bot/exts/filters/test_token_remover.py
new file mode 100644
index 000000000..f99cc3370
--- /dev/null
+++ b/tests/bot/exts/filters/test_token_remover.py
@@ -0,0 +1,408 @@
+import unittest
+from re import Match
+from unittest import mock
+from unittest.mock import MagicMock
+
+from discord import Colour, NotFound
+
+from bot import constants
+from bot.exts.filters import token_remover
+from bot.exts.filters.token_remover import Token, TokenRemover
+from bot.exts.moderation.modlog import ModLog
+from bot.utils.messages import format_user
+from tests.helpers import MockBot, MockMessage, autospec
+
+
+class TokenRemoverTests(unittest.IsolatedAsyncioTestCase):
+    """Tests the `TokenRemover` cog."""
+
+    def setUp(self):
+        """Adds the cog, a bot, and a message to the instance for usage in tests."""
+        self.bot = MockBot()
+        self.cog = TokenRemover(bot=self.bot)
+
+        self.msg = MockMessage(id=555, content="hello world")
+        self.msg.channel.mention = "#lemonade-stand"
+        self.msg.guild.get_member.return_value.bot = False
+        self.msg.guild.get_member.return_value.__str__.return_value = "Woody"
+        self.msg.author.__str__ = MagicMock(return_value=self.msg.author.name)
+        self.msg.author.avatar_url_as.return_value = "picture-lemon.png"
+
+    def test_extract_user_id_valid(self):
+        """Should consider user IDs valid if they decode into an integer ID."""
+        id_pairs = (
+            ("NDcyMjY1OTQzMDYyNDEzMzMy", 472265943062413332),
+            ("NDc1MDczNjI5Mzk5NTQ3OTA0", 475073629399547904),
+            ("NDY3MjIzMjMwNjUwNzc3NjQx", 467223230650777641),
+        )
+
+        for token_id, user_id in id_pairs:
+            with self.subTest(token_id=token_id):
+                result = TokenRemover.extract_user_id(token_id)
+                self.assertEqual(result, user_id)
+
+    def test_extract_user_id_invalid(self):
+        """Should consider non-digit and non-ASCII IDs invalid."""
+        ids = (
+            ("SGVsbG8gd29ybGQ", "non-digit ASCII"),
+            ("0J_RgNC40LLQtdGCINC80LjRgA", "cyrillic text"),
+            ("4pO14p6L4p6C4pG34p264pGl8J-EiOKSj-KCieKBsA", "Unicode digits"),
+            ("4oaA4oaB4oWh4oWi4Lyz4Lyq4Lyr4LG9", "Unicode numerals"),
+            ("8J2fjvCdn5nwnZ-k8J2fr_Cdn7rgravvvJngr6c", "Unicode decimals"),
+            ("{hello}[world]&(bye!)", "ASCII invalid Base64"),
+            ("Þíß-ï§-ňøẗ-våłìÐ", "Unicode invalid Base64"),
+        )
+
+        for user_id, msg in ids:
+            with self.subTest(msg=msg):
+                result = TokenRemover.extract_user_id(user_id)
+                self.assertIsNone(result)
+
+    def test_is_valid_timestamp_valid(self):
+        """Should consider timestamps valid if they're greater than the Discord epoch."""
+        timestamps = (
+            "XsyRkw",
+            "Xrim9Q",
+            "XsyR-w",
+            "XsySD_",
+            "Dn9r_A",
+        )
+
+        for timestamp in timestamps:
+            with self.subTest(timestamp=timestamp):
+                result = TokenRemover.is_valid_timestamp(timestamp)
+                self.assertTrue(result)
+
+    def test_is_valid_timestamp_invalid(self):
+        """Should consider timestamps invalid if they're before Discord epoch or can't be parsed."""
+        timestamps = (
+            ("B4Yffw", "DISCORD_EPOCH - TOKEN_EPOCH - 1"),
+            ("ew", "123"),
+            ("AoIKgA", "42076800"),
+            ("{hello}[world]&(bye!)", "ASCII invalid Base64"),
+            ("Þíß-ï§-ňøẗ-våłìÐ", "Unicode invalid Base64"),
+        )
+
+        for timestamp, msg in timestamps:
+            with self.subTest(msg=msg):
+                result = TokenRemover.is_valid_timestamp(timestamp)
+                self.assertFalse(result)
+
+    def test_is_valid_hmac_valid(self):
+        """Should consider an HMAC valid if it has at least 3 unique characters."""
+        valid_hmacs = (
+            "VXmErH7j511turNpfURmb0rVNm8",
+            "Ysnu2wacjaKs7qnoo46S8Dm2us8",
+            "sJf6omBPORBPju3WJEIAcwW9Zds",
+            "s45jqDV_Iisn-symw0yDRrk_jf4",
+        )
+
+        for hmac in valid_hmacs:
+            with self.subTest(msg=hmac):
+                result = TokenRemover.is_maybe_valid_hmac(hmac)
+                self.assertTrue(result)
+
+    def test_is_invalid_hmac_invalid(self):
+        """Should consider an HMAC invalid if has fewer than 3 unique characters."""
+        invalid_hmacs = (
+            ("xxxxxxxxxxxxxxxxxx", "Single character"),
+            ("XxXxXxXxXxXxXxXxXx", "Single character alternating case"),
+            ("ASFasfASFasfASFASsf", "Three characters alternating-case"),
+            ("asdasdasdasdasdasdasd", "Three characters one case"),
+        )
+
+        for hmac, msg in invalid_hmacs:
+            with self.subTest(msg=msg):
+                result = TokenRemover.is_maybe_valid_hmac(hmac)
+                self.assertFalse(result)
+
+    def test_mod_log_property(self):
+        """The `mod_log` property should ask the bot to return the `ModLog` cog."""
+        self.bot.get_cog.return_value = 'lemon'
+        self.assertEqual(self.cog.mod_log, self.bot.get_cog.return_value)
+        self.bot.get_cog.assert_called_once_with('ModLog')
+
+    async def test_on_message_edit_uses_on_message(self):
+        """The edit listener should delegate handling of the message to the normal listener."""
+        self.cog.on_message = mock.create_autospec(self.cog.on_message, spec_set=True)
+
+        await self.cog.on_message_edit(MockMessage(), self.msg)
+        self.cog.on_message.assert_awaited_once_with(self.msg)
+
+    @autospec(TokenRemover, "find_token_in_message", "take_action")
+    async def test_on_message_takes_action(self, find_token_in_message, take_action):
+        """Should take action if a valid token is found when a message is sent."""
+        cog = TokenRemover(self.bot)
+        found_token = "foobar"
+        find_token_in_message.return_value = found_token
+
+        await cog.on_message(self.msg)
+
+        find_token_in_message.assert_called_once_with(self.msg)
+        take_action.assert_awaited_once_with(cog, self.msg, found_token)
+
+    @autospec(TokenRemover, "find_token_in_message", "take_action")
+    async def test_on_message_skips_missing_token(self, find_token_in_message, take_action):
+        """Shouldn't take action if a valid token isn't found when a message is sent."""
+        cog = TokenRemover(self.bot)
+        find_token_in_message.return_value = False
+
+        await cog.on_message(self.msg)
+
+        find_token_in_message.assert_called_once_with(self.msg)
+        take_action.assert_not_awaited()
+
+    @autospec(TokenRemover, "find_token_in_message")
+    async def test_on_message_ignores_dms_bots(self, find_token_in_message):
+        """Shouldn't parse a message if it is a DM or authored by a bot."""
+        cog = TokenRemover(self.bot)
+        dm_msg = MockMessage(guild=None)
+        bot_msg = MockMessage(author=MagicMock(bot=True))
+
+        for msg in (dm_msg, bot_msg):
+            await cog.on_message(msg)
+            find_token_in_message.assert_not_called()
+
+    @autospec("bot.exts.filters.token_remover", "TOKEN_RE")
+    def test_find_token_no_matches(self, token_re):
+        """None should be returned if the regex matches no tokens in a message."""
+        token_re.finditer.return_value = ()
+
+        return_value = TokenRemover.find_token_in_message(self.msg)
+
+        self.assertIsNone(return_value)
+        token_re.finditer.assert_called_once_with(self.msg.content)
+
+    @autospec(TokenRemover, "extract_user_id", "is_valid_timestamp", "is_maybe_valid_hmac")
+    @autospec("bot.exts.filters.token_remover", "Token")
+    @autospec("bot.exts.filters.token_remover", "TOKEN_RE")
+    def test_find_token_valid_match(
+        self,
+        token_re,
+        token_cls,
+        extract_user_id,
+        is_valid_timestamp,
+        is_maybe_valid_hmac,
+    ):
+        """The first match with a valid user ID, timestamp, and HMAC should be returned as a `Token`."""
+        matches = [
+            mock.create_autospec(Match, spec_set=True, instance=True),
+            mock.create_autospec(Match, spec_set=True, instance=True),
+        ]
+        tokens = [
+            mock.create_autospec(Token, spec_set=True, instance=True),
+            mock.create_autospec(Token, spec_set=True, instance=True),
+        ]
+
+        token_re.finditer.return_value = matches
+        token_cls.side_effect = tokens
+        extract_user_id.side_effect = (None, True)  # The 1st match will be invalid, 2nd one valid.
+        is_valid_timestamp.return_value = True
+        is_maybe_valid_hmac.return_value = True
+
+        return_value = TokenRemover.find_token_in_message(self.msg)
+
+        self.assertEqual(tokens[1], return_value)
+        token_re.finditer.assert_called_once_with(self.msg.content)
+
+    @autospec(TokenRemover, "extract_user_id", "is_valid_timestamp", "is_maybe_valid_hmac")
+    @autospec("bot.exts.filters.token_remover", "Token")
+    @autospec("bot.exts.filters.token_remover", "TOKEN_RE")
+    def test_find_token_invalid_matches(
+        self,
+        token_re,
+        token_cls,
+        extract_user_id,
+        is_valid_timestamp,
+        is_maybe_valid_hmac,
+    ):
+        """None should be returned if no matches have valid user IDs, HMACs, and timestamps."""
+        token_re.finditer.return_value = [mock.create_autospec(Match, spec_set=True, instance=True)]
+        token_cls.return_value = mock.create_autospec(Token, spec_set=True, instance=True)
+        extract_user_id.return_value = None
+        is_valid_timestamp.return_value = False
+        is_maybe_valid_hmac.return_value = False
+
+        return_value = TokenRemover.find_token_in_message(self.msg)
+
+        self.assertIsNone(return_value)
+        token_re.finditer.assert_called_once_with(self.msg.content)
+
+    def test_regex_invalid_tokens(self):
+        """Messages without anything looking like a token are not matched."""
+        tokens = (
+            "",
+            "lemon wins",
+            "..",
+            "x.y",
+            "x.y.",
+            ".y.z",
+            ".y.",
+            "..z",
+            "x..z",
+            " . . ",
+            "\n.\n.\n",
+            "hellö.world.bye",
+            "base64.nötbåse64.morebase64",
+            "19jd3J.dfkm3d.€víł§tüff",
+        )
+
+        for token in tokens:
+            with self.subTest(token=token):
+                results = token_remover.TOKEN_RE.findall(token)
+                self.assertEqual(len(results), 0)
+
+    def test_regex_valid_tokens(self):
+        """Messages that look like tokens should be matched."""
+        # Don't worry, these tokens have been invalidated.
+        tokens = (
+            "NDcyMjY1OTQzMDYy_DEzMz-y.XsyRkw.VXmErH7j511turNpfURmb0rVNm8",
+            "NDcyMjY1OTQzMDYyNDEzMzMy.Xrim9Q.Ysnu2wacjaKs7qnoo46S8Dm2us8",
+            "NDc1MDczNjI5Mzk5NTQ3OTA0.XsyR-w.sJf6omBPORBPju3WJEIAcwW9Zds",
+            "NDY3MjIzMjMwNjUwNzc3NjQx.XsySD_.s45jqDV_Iisn-symw0yDRrk_jf4",
+        )
+
+        for token in tokens:
+            with self.subTest(token=token):
+                results = token_remover.TOKEN_RE.fullmatch(token)
+                self.assertIsNotNone(results, f"{token} was not matched by the regex")
+
+    def test_regex_matches_multiple_valid(self):
+        """Should support multiple matches in the middle of a string."""
+        token_1 = "NDY3MjIzMjMwNjUwNzc3NjQx.XsyWGg.uFNEQPCc4ePwGh7egG8UicQssz8"
+        token_2 = "NDcyMjY1OTQzMDYyNDEzMzMy.XsyWMw.l8XPnDqb0lp-EiQ2g_0xVFT1pyc"
+        message = f"garbage {token_1} hello {token_2} world"
+
+        results = token_remover.TOKEN_RE.finditer(message)
+        results = [match[0] for match in results]
+        self.assertCountEqual((token_1, token_2), results)
+
+    @autospec("bot.exts.filters.token_remover", "LOG_MESSAGE")
+    def test_format_log_message(self, log_message):
+        """Should correctly format the log message with info from the message and token."""
+        token = Token("NDcyMjY1OTQzMDYyNDEzMzMy", "XsySD_", "s45jqDV_Iisn-symw0yDRrk_jf4")
+        log_message.format.return_value = "Howdy"
+
+        return_value = TokenRemover.format_log_message(self.msg, token)
+
+        self.assertEqual(return_value, log_message.format.return_value)
+        log_message.format.assert_called_once_with(
+            author=format_user(self.msg.author),
+            channel=self.msg.channel.mention,
+            user_id=token.user_id,
+            timestamp=token.timestamp,
+            hmac="x" * len(token.hmac),
+        )
+
+    @autospec("bot.exts.filters.token_remover", "UNKNOWN_USER_LOG_MESSAGE")
+    def test_format_userid_log_message_unknown(self, unknown_user_log_message):
+        """Should correctly format the user ID portion when the actual user it belongs to is unknown."""
+        token = Token("NDcyMjY1OTQzMDYyNDEzMzMy", "XsySD_", "s45jqDV_Iisn-symw0yDRrk_jf4")
+        unknown_user_log_message.format.return_value = " Partner"
+        msg = MockMessage(id=555, content="hello world")
+        msg.guild.get_member.return_value = None
+
+        return_value = TokenRemover.format_userid_log_message(msg, token)
+
+        self.assertEqual(return_value, (unknown_user_log_message.format.return_value, False))
+        unknown_user_log_message.format.assert_called_once_with(user_id=472265943062413332)
+
+    @autospec("bot.exts.filters.token_remover", "KNOWN_USER_LOG_MESSAGE")
+    def test_format_userid_log_message_bot(self, known_user_log_message):
+        """Should correctly format the user ID portion when the ID belongs to a known bot."""
+        token = Token("NDcyMjY1OTQzMDYyNDEzMzMy", "XsySD_", "s45jqDV_Iisn-symw0yDRrk_jf4")
+        known_user_log_message.format.return_value = " Partner"
+        msg = MockMessage(id=555, content="hello world")
+        msg.guild.get_member.return_value.__str__.return_value = "Sam"
+        msg.guild.get_member.return_value.bot = True
+
+        return_value = TokenRemover.format_userid_log_message(msg, token)
+
+        self.assertEqual(return_value, (known_user_log_message.format.return_value, False))
+
+        known_user_log_message.format.assert_called_once_with(
+            user_id=472265943062413332,
+            user_name="Sam",
+            kind="BOT",
+        )
+
+    @autospec("bot.exts.filters.token_remover", "KNOWN_USER_LOG_MESSAGE")
+    def test_format_log_message_user_token_user(self, user_token_message):
+        """Should correctly format the user ID portion when the ID belongs to a known user."""
+        token = Token("NDY3MjIzMjMwNjUwNzc3NjQx", "XsySD_", "s45jqDV_Iisn-symw0yDRrk_jf4")
+        user_token_message.format.return_value = "Partner"
+
+        return_value = TokenRemover.format_userid_log_message(self.msg, token)
+
+        self.assertEqual(return_value, (user_token_message.format.return_value, True))
+        user_token_message.format.assert_called_once_with(
+            user_id=467223230650777641,
+            user_name="Woody",
+            kind="USER",
+        )
+
+    @mock.patch.object(TokenRemover, "mod_log", new_callable=mock.PropertyMock)
+    @autospec("bot.exts.filters.token_remover", "log")
+    @autospec(TokenRemover, "format_log_message", "format_userid_log_message")
+    async def test_take_action(self, format_log_message, format_userid_log_message, logger, mod_log_property):
+        """Should delete the message and send a mod log."""
+        cog = TokenRemover(self.bot)
+        mod_log = mock.create_autospec(ModLog, spec_set=True, instance=True)
+        token = mock.create_autospec(Token, spec_set=True, instance=True)
+        token.user_id = "no-id"
+        log_msg = "testing123"
+        userid_log_message = "userid-log-message"
+
+        mod_log_property.return_value = mod_log
+        format_log_message.return_value = log_msg
+        format_userid_log_message.return_value = (userid_log_message, True)
+
+        await cog.take_action(self.msg, token)
+
+        self.msg.delete.assert_called_once_with()
+        self.msg.channel.send.assert_called_once_with(
+            token_remover.DELETION_MESSAGE_TEMPLATE.format(mention=self.msg.author.mention)
+        )
+
+        format_log_message.assert_called_once_with(self.msg, token)
+        format_userid_log_message.assert_called_once_with(self.msg, token)
+        logger.debug.assert_called_with(log_msg)
+        self.bot.stats.incr.assert_called_once_with("tokens.removed_tokens")
+
+        mod_log.ignore.assert_called_once_with(constants.Event.message_delete, self.msg.id)
+        mod_log.send_log_message.assert_called_once_with(
+            icon_url=constants.Icons.token_removed,
+            colour=Colour(constants.Colours.soft_red),
+            title="Token removed!",
+            text=log_msg + "\n" + userid_log_message,
+            thumbnail=self.msg.author.avatar_url_as.return_value,
+            channel_id=constants.Channels.mod_alerts,
+            ping_everyone=True,
+        )
+
+    @mock.patch.object(TokenRemover, "mod_log", new_callable=mock.PropertyMock)
+    async def test_take_action_delete_failure(self, mod_log_property):
+        """Shouldn't send any messages if the token message can't be deleted."""
+        cog = TokenRemover(self.bot)
+        mod_log_property.return_value = mock.create_autospec(ModLog, spec_set=True, instance=True)
+        self.msg.delete.side_effect = NotFound(MagicMock(), MagicMock())
+
+        token = mock.create_autospec(Token, spec_set=True, instance=True)
+        await cog.take_action(self.msg, token)
+
+        self.msg.delete.assert_called_once_with()
+        self.msg.channel.send.assert_not_awaited()
+
+
+class TokenRemoverExtensionTests(unittest.TestCase):
+    """Tests for the token_remover extension."""
+
+    @autospec("bot.exts.filters.token_remover", "TokenRemover")
+    def test_extension_setup(self, cog):
+        """The TokenRemover cog should be added."""
+        bot = MockBot()
+        token_remover.setup(bot)
+
+        cog.assert_called_once_with(bot)
+        bot.add_cog.assert_called_once()
+        self.assertTrue(isinstance(bot.add_cog.call_args.args[0], TokenRemover))
diff --git a/tests/bot/exts/info/__init__.py b/tests/bot/exts/info/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/bot/exts/info/__init__.py
diff --git a/tests/bot/cogs/test_information.py b/tests/bot/exts/info/test_information.py
index 4496a2ae0..d077be960 100644
--- a/tests/bot/cogs/test_information.py
+++ b/tests/bot/exts/info/test_information.py
@@ -1,4 +1,3 @@
-import asyncio
 import textwrap
 import unittest
 import unittest.mock
@@ -6,20 +5,19 @@ import unittest.mock
 import discord
 
 from bot import constants
-from bot.cogs import information
-from bot.decorators import InChannelCheckFailure
+from bot.exts.info import information
+from bot.utils.checks import InWhitelistCheckFailure
 from tests import helpers
 
+COG_PATH = "bot.exts.info.information.Information"
 
-COG_PATH = "bot.cogs.information.Information"
 
-
-class InformationCogTests(unittest.TestCase):
+class InformationCogTests(unittest.IsolatedAsyncioTestCase):
     """Tests the Information cog."""
 
     @classmethod
     def setUpClass(cls):
-        cls.moderator_role = helpers.MockRole(name="Moderator", id=constants.Roles.moderator)
+        cls.moderator_role = helpers.MockRole(name="Moderator", id=constants.Roles.moderators)
 
     def setUp(self):
         """Sets up fresh objects for each test."""
@@ -30,27 +28,24 @@ class InformationCogTests(unittest.TestCase):
         self.ctx = helpers.MockContext()
         self.ctx.author.roles.append(self.moderator_role)
 
-    def test_roles_command_command(self):
+    async def test_roles_command_command(self):
         """Test if the `role_info` command correctly returns the `moderator_role`."""
         self.ctx.guild.roles.append(self.moderator_role)
 
-        self.cog.roles_info.can_run = helpers.AsyncMock()
+        self.cog.roles_info.can_run = unittest.mock.AsyncMock()
         self.cog.roles_info.can_run.return_value = True
 
-        coroutine = self.cog.roles_info.callback(self.cog, self.ctx)
-
-        self.assertIsNone(asyncio.run(coroutine))
+        self.assertIsNone(await self.cog.roles_info(self.cog, self.ctx))
         self.ctx.send.assert_called_once()
 
         _, kwargs = self.ctx.send.call_args
         embed = kwargs.pop('embed')
 
-        self.assertEqual(embed.title, "Role information")
+        self.assertEqual(embed.title, "Role information (Total 1 role)")
         self.assertEqual(embed.colour, discord.Colour.blurple())
-        self.assertEqual(embed.description, f"`{self.moderator_role.id}` - {self.moderator_role.mention}\n")
-        self.assertEqual(embed.footer.text, "Total roles: 1")
+        self.assertEqual(embed.description, f"\n`{self.moderator_role.id}` - {self.moderator_role.mention}\n")
 
-    def test_role_info_command(self):
+    async def test_role_info_command(self):
         """Tests the `role info` command."""
         dummy_role = helpers.MockRole(
             name="Dummy",
@@ -72,12 +67,10 @@ class InformationCogTests(unittest.TestCase):
 
         self.ctx.guild.roles.append([dummy_role, admin_role])
 
-        self.cog.role_info.can_run = helpers.AsyncMock()
+        self.cog.role_info.can_run = unittest.mock.AsyncMock()
         self.cog.role_info.can_run.return_value = True
 
-        coroutine = self.cog.role_info.callback(self.cog, self.ctx, dummy_role, admin_role)
-
-        self.assertIsNone(asyncio.run(coroutine))
+        self.assertIsNone(await self.cog.role_info(self.cog, self.ctx, dummy_role, admin_role))
 
         self.assertEqual(self.ctx.send.call_count, 2)
 
@@ -99,86 +92,18 @@ class InformationCogTests(unittest.TestCase):
         self.assertEqual(admin_embed.title, "Admins info")
         self.assertEqual(admin_embed.colour, discord.Colour.red())
 
-    @unittest.mock.patch('bot.cogs.information.time_since')
-    def test_server_info_command(self, time_since_patch):
-        time_since_patch.return_value = '2 days ago'
-
-        self.ctx.guild = helpers.MockGuild(
-            features=('lemons', 'apples'),
-            region="The Moon",
-            roles=[self.moderator_role],
-            channels=[
-                discord.TextChannel(
-                    state={},
-                    guild=self.ctx.guild,
-                    data={'id': 42, 'name': 'lemons-offering', 'position': 22, 'type': 'text'}
-                ),
-                discord.CategoryChannel(
-                    state={},
-                    guild=self.ctx.guild,
-                    data={'id': 5125, 'name': 'the-lemon-collection', 'position': 22, 'type': 'category'}
-                ),
-                discord.VoiceChannel(
-                    state={},
-                    guild=self.ctx.guild,
-                    data={'id': 15290, 'name': 'listen-to-lemon', 'position': 22, 'type': 'voice'}
-                )
-            ],
-            members=[
-                *(helpers.MockMember(status='online') for _ in range(2)),
-                *(helpers.MockMember(status='idle') for _ in range(1)),
-                *(helpers.MockMember(status='dnd') for _ in range(4)),
-                *(helpers.MockMember(status='offline') for _ in range(3)),
-            ],
-            member_count=1_234,
-            icon_url='a-lemon.jpg',
-        )
-
-        coroutine = self.cog.server_info.callback(self.cog, self.ctx)
-        self.assertIsNone(asyncio.run(coroutine))
 
-        time_since_patch.assert_called_once_with(self.ctx.guild.created_at, precision='days')
-        _, kwargs = self.ctx.send.call_args
-        embed = kwargs.pop('embed')
-        self.assertEqual(embed.colour, discord.Colour.blurple())
-        self.assertEqual(
-            embed.description,
-            textwrap.dedent(
-                f"""
-                **Server information**
-                Created: {time_since_patch.return_value}
-                Voice region: {self.ctx.guild.region}
-                Features: {', '.join(self.ctx.guild.features)}
-
-                **Counts**
-                Members: {self.ctx.guild.member_count:,}
-                Roles: {len(self.ctx.guild.roles)}
-                Text: 1
-                Voice: 1
-                Channel categories: 1
-
-                **Members**
-                {constants.Emojis.status_online} 2
-                {constants.Emojis.status_idle} 1
-                {constants.Emojis.status_dnd} 4
-                {constants.Emojis.status_offline} 3
-                """
-            )
-        )
-        self.assertEqual(embed.thumbnail.url, 'a-lemon.jpg')
-
-
-class UserInfractionHelperMethodTests(unittest.TestCase):
+class UserInfractionHelperMethodTests(unittest.IsolatedAsyncioTestCase):
     """Tests for the helper methods of the `!user` command."""
 
     def setUp(self):
         """Common set-up steps done before for each test."""
         self.bot = helpers.MockBot()
-        self.bot.api_client.get = helpers.AsyncMock()
+        self.bot.api_client.get = unittest.mock.AsyncMock()
         self.cog = information.Information(self.bot)
         self.member = helpers.MockMember(id=1234)
 
-    def test_user_command_helper_method_get_requests(self):
+    async def test_user_command_helper_method_get_requests(self):
         """The helper methods should form the correct get requests."""
         test_values = (
             {
@@ -200,11 +125,11 @@ class UserInfractionHelperMethodTests(unittest.TestCase):
             endpoint, params = test_value["expected_args"]
 
             with self.subTest(method=helper_method, endpoint=endpoint, params=params):
-                asyncio.run(helper_method(self.member))
+                await helper_method(self.member)
                 self.bot.api_client.get.assert_called_once_with(endpoint, params=params)
                 self.bot.api_client.get.reset_mock()
 
-    def _method_subtests(self, method, test_values, default_header):
+    async def _method_subtests(self, method, test_values, default_header):
         """Helper method that runs the subtests for the different helper methods."""
         for test_value in test_values:
             api_response = test_value["api response"]
@@ -213,12 +138,12 @@ class UserInfractionHelperMethodTests(unittest.TestCase):
             with self.subTest(method=method, api_response=api_response, expected_lines=expected_lines):
                 self.bot.api_client.get.return_value = api_response
 
-                expected_output = "\n".join(default_header + expected_lines)
-                actual_output = asyncio.run(method(self.member))
+                expected_output = "\n".join(expected_lines)
+                actual_output = await method(self.member)
 
-                self.assertEqual(expected_output, actual_output)
+                self.assertEqual((default_header, expected_output), actual_output)
 
-    def test_basic_user_infraction_counts_returns_correct_strings(self):
+    async def test_basic_user_infraction_counts_returns_correct_strings(self):
         """The method should correctly list both the total and active number of non-hidden infractions."""
         test_values = (
             # No infractions means zero counts
@@ -247,16 +172,16 @@ class UserInfractionHelperMethodTests(unittest.TestCase):
             },
         )
 
-        header = ["**Infractions**"]
+        header = "Infractions"
 
-        self._method_subtests(self.cog.basic_user_infraction_counts, test_values, header)
+        await self._method_subtests(self.cog.basic_user_infraction_counts, test_values, header)
 
-    def test_expanded_user_infraction_counts_returns_correct_strings(self):
+    async def test_expanded_user_infraction_counts_returns_correct_strings(self):
         """The method should correctly list the total and active number of all infractions split by infraction type."""
         test_values = (
             {
                 "api response": [],
-                "expected_lines": ["This user has never received an infraction."],
+                "expected_lines": ["No infractions"],
             },
             # Shows non-hidden inactive infraction as expected
             {
@@ -302,24 +227,24 @@ class UserInfractionHelperMethodTests(unittest.TestCase):
             },
         )
 
-        header = ["**Infractions**"]
+        header = "Infractions"
 
-        self._method_subtests(self.cog.expanded_user_infraction_counts, test_values, header)
+        await self._method_subtests(self.cog.expanded_user_infraction_counts, test_values, header)
 
-    def test_user_nomination_counts_returns_correct_strings(self):
+    async def test_user_nomination_counts_returns_correct_strings(self):
         """The method should list the number of active and historical nominations for the user."""
         test_values = (
             {
                 "api response": [],
-                "expected_lines": ["This user has never been nominated."],
+                "expected_lines": ["No nominations"],
             },
             {
                 "api response": [{'active': True}],
-                "expected_lines": ["This user is **currently** nominated (1 nomination in total)."],
+                "expected_lines": ["This user is **currently** nominated", "(1 nomination in total)"],
             },
             {
                 "api response": [{'active': True}, {'active': False}],
-                "expected_lines": ["This user is **currently** nominated (2 nominations in total)."],
+                "expected_lines": ["This user is **currently** nominated", "(2 nominations in total)"],
             },
             {
                 "api response": [{'active': False}],
@@ -332,48 +257,57 @@ class UserInfractionHelperMethodTests(unittest.TestCase):
 
         )
 
-        header = ["**Nominations**"]
+        header = "Nominations"
 
-        self._method_subtests(self.cog.user_nomination_counts, test_values, header)
+        await self._method_subtests(self.cog.user_nomination_counts, test_values, header)
 
 
[email protected]("bot.cogs.information.time_since", new=unittest.mock.MagicMock(return_value="1 year ago"))
[email protected]("bot.cogs.information.constants.MODERATION_CHANNELS", new=[50])
-class UserEmbedTests(unittest.TestCase):
[email protected]("bot.exts.info.information.time_since", new=unittest.mock.MagicMock(return_value="1 year ago"))
[email protected]("bot.exts.info.information.constants.MODERATION_CHANNELS", new=[50])
+class UserEmbedTests(unittest.IsolatedAsyncioTestCase):
     """Tests for the creation of the `!user` embed."""
 
     def setUp(self):
         """Common set-up steps done before for each test."""
         self.bot = helpers.MockBot()
-        self.bot.api_client.get = helpers.AsyncMock()
+        self.bot.api_client.get = unittest.mock.AsyncMock()
         self.cog = information.Information(self.bot)
 
-    @unittest.mock.patch(f"{COG_PATH}.basic_user_infraction_counts", new=helpers.AsyncMock(return_value=""))
-    def test_create_user_embed_uses_string_representation_of_user_in_title_if_nick_is_not_available(self):
+    @unittest.mock.patch(
+        f"{COG_PATH}.basic_user_infraction_counts",
+        new=unittest.mock.AsyncMock(return_value=("Infractions", "basic infractions"))
+    )
+    async def test_create_user_embed_uses_string_representation_of_user_in_title_if_nick_is_not_available(self):
         """The embed should use the string representation of the user if they don't have a nick."""
         ctx = helpers.MockContext(channel=helpers.MockTextChannel(id=1))
         user = helpers.MockMember()
         user.nick = None
         user.__str__ = unittest.mock.Mock(return_value="Mr. Hemlock")
 
-        embed = asyncio.run(self.cog.create_user_embed(ctx, user))
+        embed = await self.cog.create_user_embed(ctx, user)
 
         self.assertEqual(embed.title, "Mr. Hemlock")
 
-    @unittest.mock.patch(f"{COG_PATH}.basic_user_infraction_counts", new=helpers.AsyncMock(return_value=""))
-    def test_create_user_embed_uses_nick_in_title_if_available(self):
+    @unittest.mock.patch(
+        f"{COG_PATH}.basic_user_infraction_counts",
+        new=unittest.mock.AsyncMock(return_value=("Infractions", "basic infractions"))
+    )
+    async def test_create_user_embed_uses_nick_in_title_if_available(self):
         """The embed should use the nick if it's available."""
         ctx = helpers.MockContext(channel=helpers.MockTextChannel(id=1))
         user = helpers.MockMember()
         user.nick = "Cat lover"
         user.__str__ = unittest.mock.Mock(return_value="Mr. Hemlock")
 
-        embed = asyncio.run(self.cog.create_user_embed(ctx, user))
+        embed = await self.cog.create_user_embed(ctx, user)
 
         self.assertEqual(embed.title, "Cat lover (Mr. Hemlock)")
 
-    @unittest.mock.patch(f"{COG_PATH}.basic_user_infraction_counts", new=helpers.AsyncMock(return_value=""))
-    def test_create_user_embed_ignores_everyone_role(self):
+    @unittest.mock.patch(
+        f"{COG_PATH}.basic_user_infraction_counts",
+        new=unittest.mock.AsyncMock(return_value=("Infractions", "basic infractions"))
+    )
+    async def test_create_user_embed_ignores_everyone_role(self):
         """Created `!user` embeds should not contain mention of the @everyone-role."""
         ctx = helpers.MockContext(channel=helpers.MockTextChannel(id=1))
         admins_role = helpers.MockRole(name='Admins')
@@ -382,80 +316,93 @@ class UserEmbedTests(unittest.TestCase):
         # A `MockMember` has the @Everyone role by default; we add the Admins to that.
         user = helpers.MockMember(roles=[admins_role], top_role=admins_role)
 
-        embed = asyncio.run(self.cog.create_user_embed(ctx, user))
+        embed = await self.cog.create_user_embed(ctx, user)
 
-        self.assertIn("&Admins", embed.description)
-        self.assertNotIn("&Everyone", embed.description)
+        self.assertIn("&Admins", embed.fields[1].value)
+        self.assertNotIn("&Everyone", embed.fields[1].value)
 
-    @unittest.mock.patch(f"{COG_PATH}.expanded_user_infraction_counts", new_callable=helpers.AsyncMock)
-    @unittest.mock.patch(f"{COG_PATH}.user_nomination_counts", new_callable=helpers.AsyncMock)
-    def test_create_user_embed_expanded_information_in_moderation_channels(self, nomination_counts, infraction_counts):
+    @unittest.mock.patch(f"{COG_PATH}.expanded_user_infraction_counts", new_callable=unittest.mock.AsyncMock)
+    @unittest.mock.patch(f"{COG_PATH}.user_nomination_counts", new_callable=unittest.mock.AsyncMock)
+    async def test_create_user_embed_expanded_information_in_moderation_channels(
+            self,
+            nomination_counts,
+            infraction_counts
+    ):
         """The embed should contain expanded infractions and nomination info in mod channels."""
         ctx = helpers.MockContext(channel=helpers.MockTextChannel(id=50))
 
         moderators_role = helpers.MockRole(name='Moderators')
         moderators_role.colour = 100
 
-        infraction_counts.return_value = "expanded infractions info"
-        nomination_counts.return_value = "nomination info"
+        infraction_counts.return_value = ("Infractions", "expanded infractions info")
+        nomination_counts.return_value = ("Nominations", "nomination info")
 
         user = helpers.MockMember(id=314, roles=[moderators_role], top_role=moderators_role)
-        embed = asyncio.run(self.cog.create_user_embed(ctx, user))
+        embed = await self.cog.create_user_embed(ctx, user)
 
         infraction_counts.assert_called_once_with(user)
         nomination_counts.assert_called_once_with(user)
 
         self.assertEqual(
             textwrap.dedent(f"""
-                **User Information**
                 Created: {"1 year ago"}
                 Profile: {user.mention}
                 ID: {user.id}
+            """).strip(),
+            embed.fields[0].value
+        )
 
-                **Member Information**
+        self.assertEqual(
+            textwrap.dedent(f"""
                 Joined: {"1 year ago"}
+                Verified: {"True"}
                 Roles: &Moderators
-
-                expanded infractions info
-
-                nomination info
             """).strip(),
-            embed.description
+            embed.fields[1].value
         )
 
-    @unittest.mock.patch(f"{COG_PATH}.basic_user_infraction_counts", new_callable=helpers.AsyncMock)
-    def test_create_user_embed_basic_information_outside_of_moderation_channels(self, infraction_counts):
+    @unittest.mock.patch(f"{COG_PATH}.basic_user_infraction_counts", new_callable=unittest.mock.AsyncMock)
+    async def test_create_user_embed_basic_information_outside_of_moderation_channels(self, infraction_counts):
         """The embed should contain only basic infraction data outside of mod channels."""
         ctx = helpers.MockContext(channel=helpers.MockTextChannel(id=100))
 
         moderators_role = helpers.MockRole(name='Moderators')
         moderators_role.colour = 100
 
-        infraction_counts.return_value = "basic infractions info"
+        infraction_counts.return_value = ("Infractions", "basic infractions info")
 
         user = helpers.MockMember(id=314, roles=[moderators_role], top_role=moderators_role)
-        embed = asyncio.run(self.cog.create_user_embed(ctx, user))
+        embed = await self.cog.create_user_embed(ctx, user)
 
         infraction_counts.assert_called_once_with(user)
 
         self.assertEqual(
             textwrap.dedent(f"""
-                **User Information**
                 Created: {"1 year ago"}
                 Profile: {user.mention}
                 ID: {user.id}
+            """).strip(),
+            embed.fields[0].value
+        )
 
-                **Member Information**
+        self.assertEqual(
+            textwrap.dedent(f"""
                 Joined: {"1 year ago"}
                 Roles: &Moderators
-
-                basic infractions info
             """).strip(),
-            embed.description
+            embed.fields[1].value
+        )
+
+        self.assertEqual(
+            "basic infractions info",
+            embed.fields[2].value
         )
 
-    @unittest.mock.patch(f"{COG_PATH}.basic_user_infraction_counts", new=helpers.AsyncMock(return_value=""))
-    def test_create_user_embed_uses_top_role_colour_when_user_has_roles(self):
+    @unittest.mock.patch(
+        f"{COG_PATH}.basic_user_infraction_counts",
+        new=unittest.mock.AsyncMock(return_value=("Infractions", "basic infractions"))
+    )
+    async def test_create_user_embed_uses_top_role_colour_when_user_has_roles(self):
         """The embed should be created with the colour of the top role, if a top role is available."""
         ctx = helpers.MockContext()
 
@@ -463,35 +410,41 @@ class UserEmbedTests(unittest.TestCase):
         moderators_role.colour = 100
 
         user = helpers.MockMember(id=314, roles=[moderators_role], top_role=moderators_role)
-        embed = asyncio.run(self.cog.create_user_embed(ctx, user))
+        embed = await self.cog.create_user_embed(ctx, user)
 
         self.assertEqual(embed.colour, discord.Colour(moderators_role.colour))
 
-    @unittest.mock.patch(f"{COG_PATH}.basic_user_infraction_counts", new=helpers.AsyncMock(return_value=""))
-    def test_create_user_embed_uses_blurple_colour_when_user_has_no_roles(self):
+    @unittest.mock.patch(
+        f"{COG_PATH}.basic_user_infraction_counts",
+        new=unittest.mock.AsyncMock(return_value=("Infractions", "basic infractions"))
+    )
+    async def test_create_user_embed_uses_blurple_colour_when_user_has_no_roles(self):
         """The embed should be created with a blurple colour if the user has no assigned roles."""
         ctx = helpers.MockContext()
 
         user = helpers.MockMember(id=217)
-        embed = asyncio.run(self.cog.create_user_embed(ctx, user))
+        embed = await self.cog.create_user_embed(ctx, user)
 
         self.assertEqual(embed.colour, discord.Colour.blurple())
 
-    @unittest.mock.patch(f"{COG_PATH}.basic_user_infraction_counts", new=helpers.AsyncMock(return_value=""))
-    def test_create_user_embed_uses_png_format_of_user_avatar_as_thumbnail(self):
+    @unittest.mock.patch(
+        f"{COG_PATH}.basic_user_infraction_counts",
+        new=unittest.mock.AsyncMock(return_value=("Infractions", "basic infractions"))
+    )
+    async def test_create_user_embed_uses_png_format_of_user_avatar_as_thumbnail(self):
         """The embed thumbnail should be set to the user's avatar in `png` format."""
         ctx = helpers.MockContext()
 
         user = helpers.MockMember(id=217)
         user.avatar_url_as.return_value = "avatar url"
-        embed = asyncio.run(self.cog.create_user_embed(ctx, user))
+        embed = await self.cog.create_user_embed(ctx, user)
 
-        user.avatar_url_as.assert_called_once_with(format="png")
+        user.avatar_url_as.assert_called_once_with(static_format="png")
         self.assertEqual(embed.thumbnail.url, "avatar url")
 
 
[email protected]("bot.cogs.information.constants")
-class UserCommandTests(unittest.TestCase):
[email protected]("bot.exts.info.information.constants")
+class UserCommandTests(unittest.IsolatedAsyncioTestCase):
     """Tests for the `!user` command."""
 
     def setUp(self):
@@ -507,76 +460,70 @@ class UserCommandTests(unittest.TestCase):
         self.moderator = helpers.MockMember(id=2, name="riffautae", roles=[self.moderator_role])
         self.target = helpers.MockMember(id=3, name="__fluzz__")
 
-    def test_regular_member_cannot_target_another_member(self, constants):
+        # There's no way to mock the channel constant without deferring imports. The constant is
+        # used as a default value for a parameter, which gets defined upon import.
+        self.bot_command_channel = helpers.MockTextChannel(id=constants.Channels.bot_commands)
+
+    async def test_regular_member_cannot_target_another_member(self, constants):
         """A regular user should not be able to use `!user` targeting another user."""
         constants.MODERATION_ROLES = [self.moderator_role.id]
-
         ctx = helpers.MockContext(author=self.author)
 
-        asyncio.run(self.cog.user_info.callback(self.cog, ctx, self.target))
+        await self.cog.user_info(self.cog, ctx, self.target)
 
         ctx.send.assert_called_once_with("You may not use this command on users other than yourself.")
 
-    def test_regular_member_cannot_use_command_outside_of_bot_commands(self, constants):
+    async def test_regular_member_cannot_use_command_outside_of_bot_commands(self, constants):
         """A regular user should not be able to use this command outside of bot-commands."""
         constants.MODERATION_ROLES = [self.moderator_role.id]
         constants.STAFF_ROLES = [self.moderator_role.id]
-        constants.Channels.bot = 50
-
         ctx = helpers.MockContext(author=self.author, channel=helpers.MockTextChannel(id=100))
 
         msg = "Sorry, but you may only use this command within <#50>."
-        with self.assertRaises(InChannelCheckFailure, msg=msg):
-            asyncio.run(self.cog.user_info.callback(self.cog, ctx))
+        with self.assertRaises(InWhitelistCheckFailure, msg=msg):
+            await self.cog.user_info(self.cog, ctx)
 
-    @unittest.mock.patch("bot.cogs.information.Information.create_user_embed", new_callable=helpers.AsyncMock)
-    def test_regular_user_may_use_command_in_bot_commands_channel(self, create_embed, constants):
+    @unittest.mock.patch("bot.exts.info.information.Information.create_user_embed")
+    async def test_regular_user_may_use_command_in_bot_commands_channel(self, create_embed, constants):
         """A regular user should be allowed to use `!user` targeting themselves in bot-commands."""
         constants.STAFF_ROLES = [self.moderator_role.id]
-        constants.Channels.bot = 50
+        ctx = helpers.MockContext(author=self.author, channel=self.bot_command_channel)
 
-        ctx = helpers.MockContext(author=self.author, channel=helpers.MockTextChannel(id=50))
-
-        asyncio.run(self.cog.user_info.callback(self.cog, ctx))
+        await self.cog.user_info(self.cog, ctx)
 
         create_embed.assert_called_once_with(ctx, self.author)
         ctx.send.assert_called_once()
 
-    @unittest.mock.patch("bot.cogs.information.Information.create_user_embed", new_callable=helpers.AsyncMock)
-    def test_regular_user_can_explicitly_target_themselves(self, create_embed, constants):
+    @unittest.mock.patch("bot.exts.info.information.Information.create_user_embed")
+    async def test_regular_user_can_explicitly_target_themselves(self, create_embed, _):
         """A user should target itself with `!user` when a `user` argument was not provided."""
         constants.STAFF_ROLES = [self.moderator_role.id]
-        constants.Channels.bot = 50
-
-        ctx = helpers.MockContext(author=self.author, channel=helpers.MockTextChannel(id=50))
+        ctx = helpers.MockContext(author=self.author, channel=self.bot_command_channel)
 
-        asyncio.run(self.cog.user_info.callback(self.cog, ctx, self.author))
+        await self.cog.user_info(self.cog, ctx, self.author)
 
         create_embed.assert_called_once_with(ctx, self.author)
         ctx.send.assert_called_once()
 
-    @unittest.mock.patch("bot.cogs.information.Information.create_user_embed", new_callable=helpers.AsyncMock)
-    def test_staff_members_can_bypass_channel_restriction(self, create_embed, constants):
+    @unittest.mock.patch("bot.exts.info.information.Information.create_user_embed")
+    async def test_staff_members_can_bypass_channel_restriction(self, create_embed, constants):
         """Staff members should be able to bypass the bot-commands channel restriction."""
         constants.STAFF_ROLES = [self.moderator_role.id]
-        constants.Channels.bot = 50
-
         ctx = helpers.MockContext(author=self.moderator, channel=helpers.MockTextChannel(id=200))
 
-        asyncio.run(self.cog.user_info.callback(self.cog, ctx))
+        await self.cog.user_info(self.cog, ctx)
 
         create_embed.assert_called_once_with(ctx, self.moderator)
         ctx.send.assert_called_once()
 
-    @unittest.mock.patch("bot.cogs.information.Information.create_user_embed", new_callable=helpers.AsyncMock)
-    def test_moderators_can_target_another_member(self, create_embed, constants):
+    @unittest.mock.patch("bot.exts.info.information.Information.create_user_embed")
+    async def test_moderators_can_target_another_member(self, create_embed, constants):
         """A moderator should be able to use `!user` targeting another user."""
         constants.MODERATION_ROLES = [self.moderator_role.id]
         constants.STAFF_ROLES = [self.moderator_role.id]
-
         ctx = helpers.MockContext(author=self.moderator, channel=helpers.MockTextChannel(id=50))
 
-        asyncio.run(self.cog.user_info.callback(self.cog, ctx, self.target))
+        await self.cog.user_info(self.cog, ctx, self.target)
 
         create_embed.assert_called_once_with(ctx, self.target)
         ctx.send.assert_called_once()
diff --git a/tests/bot/exts/moderation/__init__.py b/tests/bot/exts/moderation/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/bot/exts/moderation/__init__.py
diff --git a/tests/bot/exts/moderation/infraction/__init__.py b/tests/bot/exts/moderation/infraction/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/bot/exts/moderation/infraction/__init__.py
diff --git a/tests/bot/exts/moderation/infraction/test_infractions.py b/tests/bot/exts/moderation/infraction/test_infractions.py
new file mode 100644
index 000000000..bf557a484
--- /dev/null
+++ b/tests/bot/exts/moderation/infraction/test_infractions.py
@@ -0,0 +1,201 @@
+import textwrap
+import unittest
+from unittest.mock import AsyncMock, MagicMock, Mock, patch
+
+from bot.constants import Event
+from bot.exts.moderation.infraction.infractions import Infractions
+from tests.helpers import MockBot, MockContext, MockGuild, MockMember, MockRole
+
+
+class TruncationTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for ban and kick command reason truncation."""
+
+    def setUp(self):
+        self.bot = MockBot()
+        self.cog = Infractions(self.bot)
+        self.user = MockMember(id=1234, top_role=MockRole(id=3577, position=10))
+        self.target = MockMember(id=1265, top_role=MockRole(id=9876, position=0))
+        self.guild = MockGuild(id=4567)
+        self.ctx = MockContext(bot=self.bot, author=self.user, guild=self.guild)
+
+    @patch("bot.exts.moderation.infraction._utils.get_active_infraction")
+    @patch("bot.exts.moderation.infraction._utils.post_infraction")
+    async def test_apply_ban_reason_truncation(self, post_infraction_mock, get_active_mock):
+        """Should truncate reason for `ctx.guild.ban`."""
+        get_active_mock.return_value = None
+        post_infraction_mock.return_value = {"foo": "bar"}
+
+        self.cog.apply_infraction = AsyncMock()
+        self.bot.get_cog.return_value = AsyncMock()
+        self.cog.mod_log.ignore = Mock()
+        self.ctx.guild.ban = Mock()
+
+        await self.cog.apply_ban(self.ctx, self.target, "foo bar" * 3000)
+        self.ctx.guild.ban.assert_called_once_with(
+            self.target,
+            reason=textwrap.shorten("foo bar" * 3000, 512, placeholder="..."),
+            delete_message_days=0
+        )
+        self.cog.apply_infraction.assert_awaited_once_with(
+            self.ctx, {"foo": "bar"}, self.target, self.ctx.guild.ban.return_value
+        )
+
+    @patch("bot.exts.moderation.infraction._utils.post_infraction")
+    async def test_apply_kick_reason_truncation(self, post_infraction_mock):
+        """Should truncate reason for `Member.kick`."""
+        post_infraction_mock.return_value = {"foo": "bar"}
+
+        self.cog.apply_infraction = AsyncMock()
+        self.cog.mod_log.ignore = Mock()
+        self.target.kick = Mock()
+
+        await self.cog.apply_kick(self.ctx, self.target, "foo bar" * 3000)
+        self.target.kick.assert_called_once_with(reason=textwrap.shorten("foo bar" * 3000, 512, placeholder="..."))
+        self.cog.apply_infraction.assert_awaited_once_with(
+            self.ctx, {"foo": "bar"}, self.target, self.target.kick.return_value
+        )
+
+
+@patch("bot.exts.moderation.infraction.infractions.constants.Roles.voice_verified", new=123456)
+class VoiceBanTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for voice ban related functions and commands."""
+
+    def setUp(self):
+        self.bot = MockBot()
+        self.mod = MockMember(top_role=10)
+        self.user = MockMember(top_role=1, roles=[MockRole(id=123456)])
+        self.guild = MockGuild()
+        self.ctx = MockContext(bot=self.bot, author=self.mod)
+        self.cog = Infractions(self.bot)
+
+    async def test_permanent_voice_ban(self):
+        """Should call voice ban applying function without expiry."""
+        self.cog.apply_voice_ban = AsyncMock()
+        self.assertIsNone(await self.cog.voiceban(self.cog, self.ctx, self.user, reason="foobar"))
+        self.cog.apply_voice_ban.assert_awaited_once_with(self.ctx, self.user, "foobar")
+
+    async def test_temporary_voice_ban(self):
+        """Should call voice ban applying function with expiry."""
+        self.cog.apply_voice_ban = AsyncMock()
+        self.assertIsNone(await self.cog.tempvoiceban(self.cog, self.ctx, self.user, "baz", reason="foobar"))
+        self.cog.apply_voice_ban.assert_awaited_once_with(self.ctx, self.user, "foobar", expires_at="baz")
+
+    async def test_voice_unban(self):
+        """Should call infraction pardoning function."""
+        self.cog.pardon_infraction = AsyncMock()
+        self.assertIsNone(await self.cog.unvoiceban(self.cog, self.ctx, self.user))
+        self.cog.pardon_infraction.assert_awaited_once_with(self.ctx, "voice_ban", self.user)
+
+    @patch("bot.exts.moderation.infraction.infractions._utils.post_infraction")
+    @patch("bot.exts.moderation.infraction.infractions._utils.get_active_infraction")
+    async def test_voice_ban_user_have_active_infraction(self, get_active_infraction, post_infraction_mock):
+        """Should return early when user already have Voice Ban infraction."""
+        get_active_infraction.return_value = {"foo": "bar"}
+        self.assertIsNone(await self.cog.apply_voice_ban(self.ctx, self.user, "foobar"))
+        get_active_infraction.assert_awaited_once_with(self.ctx, self.user, "voice_ban")
+        post_infraction_mock.assert_not_awaited()
+
+    @patch("bot.exts.moderation.infraction.infractions._utils.post_infraction")
+    @patch("bot.exts.moderation.infraction.infractions._utils.get_active_infraction")
+    async def test_voice_ban_infraction_post_failed(self, get_active_infraction, post_infraction_mock):
+        """Should return early when posting infraction fails."""
+        self.cog.mod_log.ignore = MagicMock()
+        get_active_infraction.return_value = None
+        post_infraction_mock.return_value = None
+        self.assertIsNone(await self.cog.apply_voice_ban(self.ctx, self.user, "foobar"))
+        post_infraction_mock.assert_awaited_once()
+        self.cog.mod_log.ignore.assert_not_called()
+
+    @patch("bot.exts.moderation.infraction.infractions._utils.post_infraction")
+    @patch("bot.exts.moderation.infraction.infractions._utils.get_active_infraction")
+    async def test_voice_ban_infraction_post_add_kwargs(self, get_active_infraction, post_infraction_mock):
+        """Should pass all kwargs passed to apply_voice_ban to post_infraction."""
+        get_active_infraction.return_value = None
+        # We don't want that this continue yet
+        post_infraction_mock.return_value = None
+        self.assertIsNone(await self.cog.apply_voice_ban(self.ctx, self.user, "foobar", my_kwarg=23))
+        post_infraction_mock.assert_awaited_once_with(
+            self.ctx, self.user, "voice_ban", "foobar", active=True, my_kwarg=23
+        )
+
+    @patch("bot.exts.moderation.infraction.infractions._utils.post_infraction")
+    @patch("bot.exts.moderation.infraction.infractions._utils.get_active_infraction")
+    async def test_voice_ban_mod_log_ignore(self, get_active_infraction, post_infraction_mock):
+        """Should ignore Voice Verified role removing."""
+        self.cog.mod_log.ignore = MagicMock()
+        self.cog.apply_infraction = AsyncMock()
+        self.user.remove_roles = MagicMock(return_value="my_return_value")
+
+        get_active_infraction.return_value = None
+        post_infraction_mock.return_value = {"foo": "bar"}
+
+        self.assertIsNone(await self.cog.apply_voice_ban(self.ctx, self.user, "foobar"))
+        self.cog.mod_log.ignore.assert_called_once_with(Event.member_update, self.user.id)
+
+    @patch("bot.exts.moderation.infraction.infractions._utils.post_infraction")
+    @patch("bot.exts.moderation.infraction.infractions._utils.get_active_infraction")
+    async def test_voice_ban_apply_infraction(self, get_active_infraction, post_infraction_mock):
+        """Should ignore Voice Verified role removing."""
+        self.cog.mod_log.ignore = MagicMock()
+        self.cog.apply_infraction = AsyncMock()
+        self.user.remove_roles = MagicMock(return_value="my_return_value")
+
+        get_active_infraction.return_value = None
+        post_infraction_mock.return_value = {"foo": "bar"}
+
+        self.assertIsNone(await self.cog.apply_voice_ban(self.ctx, self.user, "foobar"))
+        self.user.remove_roles.assert_called_once_with(self.cog._voice_verified_role, reason="foobar")
+        self.cog.apply_infraction.assert_awaited_once_with(self.ctx, {"foo": "bar"}, self.user, "my_return_value")
+
+    @patch("bot.exts.moderation.infraction.infractions._utils.post_infraction")
+    @patch("bot.exts.moderation.infraction.infractions._utils.get_active_infraction")
+    async def test_voice_ban_truncate_reason(self, get_active_infraction, post_infraction_mock):
+        """Should truncate reason for voice ban."""
+        self.cog.mod_log.ignore = MagicMock()
+        self.cog.apply_infraction = AsyncMock()
+        self.user.remove_roles = MagicMock(return_value="my_return_value")
+
+        get_active_infraction.return_value = None
+        post_infraction_mock.return_value = {"foo": "bar"}
+
+        self.assertIsNone(await self.cog.apply_voice_ban(self.ctx, self.user, "foobar" * 3000))
+        self.user.remove_roles.assert_called_once_with(
+            self.cog._voice_verified_role, reason=textwrap.shorten("foobar" * 3000, 512, placeholder="...")
+        )
+        self.cog.apply_infraction.assert_awaited_once_with(self.ctx, {"foo": "bar"}, self.user, "my_return_value")
+
+    async def test_voice_unban_user_not_found(self):
+        """Should include info to return dict when user was not found from guild."""
+        self.guild.get_member.return_value = None
+        result = await self.cog.pardon_voice_ban(self.user.id, self.guild, "foobar")
+        self.assertEqual(result, {"Info": "User was not found in the guild."})
+
+    @patch("bot.exts.moderation.infraction.infractions._utils.notify_pardon")
+    @patch("bot.exts.moderation.infraction.infractions.format_user")
+    async def test_voice_unban_user_found(self, format_user_mock, notify_pardon_mock):
+        """Should add role back with ignoring, notify user and return log dictionary.."""
+        self.guild.get_member.return_value = self.user
+        notify_pardon_mock.return_value = True
+        format_user_mock.return_value = "my-user"
+
+        result = await self.cog.pardon_voice_ban(self.user.id, self.guild, "foobar")
+        self.assertEqual(result, {
+            "Member": "my-user",
+            "DM": "Sent"
+        })
+        notify_pardon_mock.assert_awaited_once()
+
+    @patch("bot.exts.moderation.infraction.infractions._utils.notify_pardon")
+    @patch("bot.exts.moderation.infraction.infractions.format_user")
+    async def test_voice_unban_dm_fail(self, format_user_mock, notify_pardon_mock):
+        """Should add role back with ignoring, notify user and return log dictionary.."""
+        self.guild.get_member.return_value = self.user
+        notify_pardon_mock.return_value = False
+        format_user_mock.return_value = "my-user"
+
+        result = await self.cog.pardon_voice_ban(self.user.id, self.guild, "foobar")
+        self.assertEqual(result, {
+            "Member": "my-user",
+            "DM": "**Failed**"
+        })
+        notify_pardon_mock.assert_awaited_once()
diff --git a/tests/bot/exts/moderation/infraction/test_utils.py b/tests/bot/exts/moderation/infraction/test_utils.py
new file mode 100644
index 000000000..5b62463e0
--- /dev/null
+++ b/tests/bot/exts/moderation/infraction/test_utils.py
@@ -0,0 +1,359 @@
+import unittest
+from collections import namedtuple
+from datetime import datetime
+from unittest.mock import AsyncMock, MagicMock, call, patch
+
+from discord import Embed, Forbidden, HTTPException, NotFound
+
+from bot.api import ResponseCodeError
+from bot.constants import Colours, Icons
+from bot.exts.moderation.infraction import _utils as utils
+from tests.helpers import MockBot, MockContext, MockMember, MockUser
+
+
+class ModerationUtilsTests(unittest.IsolatedAsyncioTestCase):
+    """Tests Moderation utils."""
+
+    def setUp(self):
+        self.bot = MockBot()
+        self.member = MockMember(id=1234)
+        self.user = MockUser(id=1234)
+        self.ctx = MockContext(bot=self.bot, author=self.member)
+
+    async def test_post_user(self):
+        """Should POST a new user and return the response if successful or otherwise send an error message."""
+        user = MockUser(discriminator=5678, id=1234, name="Test user")
+        not_user = MagicMock(discriminator=3333, id=5678, name="Wrong user")
+        test_cases = [
+            {
+                "user": user,
+                "post_result": "bar",
+                "raise_error": None,
+                "payload": {
+                    "discriminator": 5678,
+                    "id": self.user.id,
+                    "in_guild": False,
+                    "name": "Test user",
+                    "roles": []
+                }
+            },
+            {
+                "user": self.member,
+                "post_result": "foo",
+                "raise_error": ResponseCodeError(MagicMock(status=400), "foo"),
+                "payload": {
+                    "discriminator": 0,
+                    "id": self.member.id,
+                    "in_guild": False,
+                    "name": "Name unknown",
+                    "roles": []
+                }
+            },
+            {
+                "user": not_user,
+                "post_result": "bar",
+                "raise_error": None,
+                "payload": {
+                    "discriminator": not_user.discriminator,
+                    "id": not_user.id,
+                    "in_guild": False,
+                    "name": not_user.name,
+                    "roles": []
+                }
+            }
+        ]
+
+        for case in test_cases:
+            user = case["user"]
+            post_result = case["post_result"]
+            raise_error = case["raise_error"]
+            payload = case["payload"]
+
+            with self.subTest(user=user, post_result=post_result, raise_error=raise_error, payload=payload):
+                self.bot.api_client.post.reset_mock(side_effect=True)
+                self.ctx.bot.api_client.post.return_value = post_result
+
+                self.ctx.bot.api_client.post.side_effect = raise_error
+
+                result = await utils.post_user(self.ctx, user)
+
+                if raise_error:
+                    self.assertIsNone(result)
+                    self.ctx.send.assert_awaited_once()
+                    self.assertIn(str(raise_error.status), self.ctx.send.call_args[0][0])
+                else:
+                    self.assertEqual(result, post_result)
+                    self.bot.api_client.post.assert_awaited_once_with("bot/users", json=payload)
+
+    async def test_get_active_infraction(self):
+        """
+        Should request the API for active infractions and return infraction if the user has one or `None` otherwise.
+
+        A message should be sent to the context indicating a user already has an infraction, if that's the case.
+        """
+        test_case = namedtuple("test_case", ["get_return_value", "expected_output", "infraction_nr", "send_msg"])
+        test_cases = [
+            test_case([], None, None, True),
+            test_case([{"id": 123987}], {"id": 123987}, "123987", False),
+            test_case([{"id": 123987}], {"id": 123987}, "123987", True)
+        ]
+
+        for case in test_cases:
+            with self.subTest(return_value=case.get_return_value, expected=case.expected_output):
+                self.bot.api_client.get.reset_mock()
+                self.ctx.send.reset_mock()
+
+                params = {
+                    "active": "true",
+                    "type": "ban",
+                    "user__id": str(self.member.id)
+                }
+
+                self.bot.api_client.get.return_value = case.get_return_value
+
+                result = await utils.get_active_infraction(self.ctx, self.member, "ban", send_msg=case.send_msg)
+                self.assertEqual(result, case.expected_output)
+                self.bot.api_client.get.assert_awaited_once_with("bot/infractions", params=params)
+
+                if case.send_msg and case.get_return_value:
+                    self.ctx.send.assert_awaited_once()
+                    sent_message = self.ctx.send.call_args[0][0]
+                    self.assertIn(case.infraction_nr, sent_message)
+                    self.assertIn("ban", sent_message)
+                else:
+                    self.ctx.send.assert_not_awaited()
+
+    @patch("bot.exts.moderation.infraction._utils.send_private_embed")
+    async def test_notify_infraction(self, send_private_embed_mock):
+        """
+        Should send an embed of a certain format as a DM and return `True` if DM successful.
+
+        Appealable infractions should have the appeal message in the embed's footer.
+        """
+        test_cases = [
+            {
+                "args": (self.user, "ban", "2020-02-26 09:20 (23 hours and 59 minutes)"),
+                "expected_output": Embed(
+                    title=utils.INFRACTION_TITLE,
+                    description=utils.INFRACTION_DESCRIPTION_TEMPLATE.format(
+                        type="Ban",
+                        expires="2020-02-26 09:20 (23 hours and 59 minutes)",
+                        reason="No reason provided."
+                    ),
+                    colour=Colours.soft_red,
+                    url=utils.RULES_URL
+                ).set_author(
+                    name=utils.INFRACTION_AUTHOR_NAME,
+                    url=utils.RULES_URL,
+                    icon_url=Icons.token_removed
+                ).set_footer(text=utils.INFRACTION_APPEAL_FOOTER),
+                "send_result": True
+            },
+            {
+                "args": (self.user, "warning", None, "Test reason."),
+                "expected_output": Embed(
+                    title=utils.INFRACTION_TITLE,
+                    description=utils.INFRACTION_DESCRIPTION_TEMPLATE.format(
+                        type="Warning",
+                        expires="N/A",
+                        reason="Test reason."
+                    ),
+                    colour=Colours.soft_red,
+                    url=utils.RULES_URL
+                ).set_author(
+                    name=utils.INFRACTION_AUTHOR_NAME,
+                    url=utils.RULES_URL,
+                    icon_url=Icons.token_removed
+                ),
+                "send_result": False
+            },
+            {
+                "args": (self.user, "note", None, None, Icons.defcon_denied),
+                "expected_output": Embed(
+                    title=utils.INFRACTION_TITLE,
+                    description=utils.INFRACTION_DESCRIPTION_TEMPLATE.format(
+                        type="Note",
+                        expires="N/A",
+                        reason="No reason provided."
+                    ),
+                    colour=Colours.soft_red,
+                    url=utils.RULES_URL
+                ).set_author(
+                    name=utils.INFRACTION_AUTHOR_NAME,
+                    url=utils.RULES_URL,
+                    icon_url=Icons.defcon_denied
+                ),
+                "send_result": False
+            },
+            {
+                "args": (self.user, "mute", "2020-02-26 09:20 (23 hours and 59 minutes)", "Test", Icons.defcon_denied),
+                "expected_output": Embed(
+                    title=utils.INFRACTION_TITLE,
+                    description=utils.INFRACTION_DESCRIPTION_TEMPLATE.format(
+                        type="Mute",
+                        expires="2020-02-26 09:20 (23 hours and 59 minutes)",
+                        reason="Test"
+                    ),
+                    colour=Colours.soft_red,
+                    url=utils.RULES_URL
+                ).set_author(
+                    name=utils.INFRACTION_AUTHOR_NAME,
+                    url=utils.RULES_URL,
+                    icon_url=Icons.defcon_denied
+                ).set_footer(text=utils.INFRACTION_APPEAL_FOOTER),
+                "send_result": False
+            },
+            {
+                "args": (self.user, "mute", None, "foo bar" * 4000, Icons.defcon_denied),
+                "expected_output": Embed(
+                    title=utils.INFRACTION_TITLE,
+                    description=utils.INFRACTION_DESCRIPTION_TEMPLATE.format(
+                        type="Mute",
+                        expires="N/A",
+                        reason="foo bar" * 4000
+                    )[:2045] + "...",
+                    colour=Colours.soft_red,
+                    url=utils.RULES_URL
+                ).set_author(
+                    name=utils.INFRACTION_AUTHOR_NAME,
+                    url=utils.RULES_URL,
+                    icon_url=Icons.defcon_denied
+                ).set_footer(text=utils.INFRACTION_APPEAL_FOOTER),
+                "send_result": True
+            }
+        ]
+
+        for case in test_cases:
+            with self.subTest(args=case["args"], expected=case["expected_output"], send=case["send_result"]):
+                send_private_embed_mock.reset_mock()
+
+                send_private_embed_mock.return_value = case["send_result"]
+                result = await utils.notify_infraction(*case["args"])
+
+                self.assertEqual(case["send_result"], result)
+
+                embed = send_private_embed_mock.call_args[0][1]
+
+                self.assertEqual(embed.to_dict(), case["expected_output"].to_dict())
+
+                send_private_embed_mock.assert_awaited_once_with(case["args"][0], embed)
+
+    @patch("bot.exts.moderation.infraction._utils.send_private_embed")
+    async def test_notify_pardon(self, send_private_embed_mock):
+        """Should send an embed of a certain format as a DM and return `True` if DM successful."""
+        test_case = namedtuple("test_case", ["args", "icon", "send_result"])
+        test_cases = [
+            test_case((self.user, "Test title", "Example content"), Icons.user_verified, True),
+            test_case((self.user, "Test title", "Example content", Icons.user_update), Icons.user_update, False)
+        ]
+
+        for case in test_cases:
+            expected = Embed(
+                description="Example content",
+                colour=Colours.soft_green
+            ).set_author(
+                name="Test title",
+                icon_url=case.icon
+            )
+
+            with self.subTest(args=case.args, expected=expected):
+                send_private_embed_mock.reset_mock()
+
+                send_private_embed_mock.return_value = case.send_result
+
+                result = await utils.notify_pardon(*case.args)
+                self.assertEqual(case.send_result, result)
+
+                embed = send_private_embed_mock.call_args[0][1]
+                self.assertEqual(embed.to_dict(), expected.to_dict())
+
+                send_private_embed_mock.assert_awaited_once_with(case.args[0], embed)
+
+    async def test_send_private_embed(self):
+        """Should DM the user and return `True` on success or `False` on failure."""
+        embed = Embed(title="Test", description="Test val")
+
+        test_case = namedtuple("test_case", ["expected_output", "raised_exception"])
+        test_cases = [
+            test_case(True, None),
+            test_case(False, HTTPException(AsyncMock(), AsyncMock())),
+            test_case(False, Forbidden(AsyncMock(), AsyncMock())),
+            test_case(False, NotFound(AsyncMock(), AsyncMock()))
+        ]
+
+        for case in test_cases:
+            with self.subTest(expected=case.expected_output, raised=case.raised_exception):
+                self.user.send.reset_mock(side_effect=True)
+                self.user.send.side_effect = case.raised_exception
+
+                result = await utils.send_private_embed(self.user, embed)
+
+                self.assertEqual(result, case.expected_output)
+                self.user.send.assert_awaited_once_with(embed=embed)
+
+
+class TestPostInfraction(unittest.IsolatedAsyncioTestCase):
+    """Tests for the `post_infraction` function."""
+
+    def setUp(self):
+        self.bot = MockBot()
+        self.member = MockMember(id=1234)
+        self.user = MockUser(id=1234)
+        self.ctx = MockContext(bot=self.bot, author=self.member)
+
+    async def test_normal_post_infraction(self):
+        """Should return response from POST request if there are no errors."""
+        now = datetime.now()
+        payload = {
+            "actor": self.ctx.author.id,
+            "hidden": True,
+            "reason": "Test reason",
+            "type": "ban",
+            "user": self.member.id,
+            "active": False,
+            "expires_at": now.isoformat()
+        }
+
+        self.ctx.bot.api_client.post.return_value = "foo"
+        actual = await utils.post_infraction(self.ctx, self.member, "ban", "Test reason", now, True, False)
+
+        self.assertEqual(actual, "foo")
+        self.ctx.bot.api_client.post.assert_awaited_once_with("bot/infractions", json=payload)
+
+    async def test_unknown_error_post_infraction(self):
+        """Should send an error message to chat when a non-400 error occurs."""
+        self.ctx.bot.api_client.post.side_effect = ResponseCodeError(AsyncMock(), AsyncMock())
+        self.ctx.bot.api_client.post.side_effect.status = 500
+
+        actual = await utils.post_infraction(self.ctx, self.user, "ban", "Test reason")
+        self.assertIsNone(actual)
+
+        self.assertTrue("500" in self.ctx.send.call_args[0][0])
+
+    @patch("bot.exts.moderation.infraction._utils.post_user", return_value=None)
+    async def test_user_not_found_none_post_infraction(self, post_user_mock):
+        """Should abort and return `None` when a new user fails to be posted."""
+        self.bot.api_client.post.side_effect = ResponseCodeError(MagicMock(status=400), {"user": "foo"})
+
+        actual = await utils.post_infraction(self.ctx, self.user, "mute", "Test reason")
+        self.assertIsNone(actual)
+        post_user_mock.assert_awaited_once_with(self.ctx, self.user)
+
+    @patch("bot.exts.moderation.infraction._utils.post_user", return_value="bar")
+    async def test_first_fail_second_success_user_post_infraction(self, post_user_mock):
+        """Should post the user if they don't exist, POST infraction again, and return the response if successful."""
+        payload = {
+            "actor": self.ctx.author.id,
+            "hidden": False,
+            "reason": "Test reason",
+            "type": "mute",
+            "user": self.user.id,
+            "active": True
+        }
+
+        self.bot.api_client.post.side_effect = [ResponseCodeError(MagicMock(status=400), {"user": "foo"}), "foo"]
+
+        actual = await utils.post_infraction(self.ctx, self.user, "mute", "Test reason")
+        self.assertEqual(actual, "foo")
+        self.bot.api_client.post.assert_has_awaits([call("bot/infractions", json=payload)] * 2)
+        post_user_mock.assert_awaited_once_with(self.ctx, self.user)
diff --git a/tests/bot/exts/moderation/test_incidents.py b/tests/bot/exts/moderation/test_incidents.py
new file mode 100644
index 000000000..cbf7f7bcf
--- /dev/null
+++ b/tests/bot/exts/moderation/test_incidents.py
@@ -0,0 +1,770 @@
+import asyncio
+import enum
+import logging
+import typing as t
+import unittest
+from unittest.mock import AsyncMock, MagicMock, call, patch
+
+import aiohttp
+import discord
+
+from bot.constants import Colours
+from bot.exts.moderation import incidents
+from tests.helpers import (
+    MockAsyncWebhook,
+    MockAttachment,
+    MockBot,
+    MockMember,
+    MockMessage,
+    MockReaction,
+    MockRole,
+    MockTextChannel,
+    MockUser,
+)
+
+
+class MockAsyncIterable:
+    """
+    Helper for mocking asynchronous for loops.
+
+    It does not appear that the `unittest` library currently provides anything that would
+    allow us to simply mock an async iterator, such as `discord.TextChannel.history`.
+
+    We therefore write our own helper to wrap a regular synchronous iterable, and feed
+    its values via `__anext__` rather than `__next__`.
+
+    This class was written for the purposes of testing the `Incidents` cog - it may not
+    be generic enough to be placed in the `tests.helpers` module.
+    """
+
+    def __init__(self, messages: t.Iterable):
+        """Take a sync iterable to be wrapped."""
+        self.iter_messages = iter(messages)
+
+    def __aiter__(self):
+        """Return `self` as we provide the `__anext__` method."""
+        return self
+
+    async def __anext__(self):
+        """
+        Feed the next item, or raise `StopAsyncIteration`.
+
+        Since we're wrapping a sync iterator, it will communicate that it has been depleted
+        by raising a `StopIteration`. The `async for` construct does not expect it, and we
+        therefore need to substitute it for the appropriate exception type.
+        """
+        try:
+            return next(self.iter_messages)
+        except StopIteration:
+            raise StopAsyncIteration
+
+
+class MockSignal(enum.Enum):
+    A = "A"
+    B = "B"
+
+
+mock_404 = discord.NotFound(
+    response=MagicMock(aiohttp.ClientResponse),  # Mock the erroneous response
+    message="Not found",
+)
+
+
+class TestDownloadFile(unittest.IsolatedAsyncioTestCase):
+    """Collection of tests for the `download_file` helper function."""
+
+    async def test_download_file_success(self):
+        """If `to_file` succeeds, function returns the acquired `discord.File`."""
+        file = MagicMock(discord.File, filename="bigbadlemon.jpg")
+        attachment = MockAttachment(to_file=AsyncMock(return_value=file))
+
+        acquired_file = await incidents.download_file(attachment)
+        self.assertIs(file, acquired_file)
+
+    async def test_download_file_404(self):
+        """If `to_file` encounters a 404, function handles the exception & returns None."""
+        attachment = MockAttachment(to_file=AsyncMock(side_effect=mock_404))
+
+        acquired_file = await incidents.download_file(attachment)
+        self.assertIsNone(acquired_file)
+
+    async def test_download_file_fail(self):
+        """If `to_file` fails on a non-404 error, function logs the exception & returns None."""
+        arbitrary_error = discord.HTTPException(MagicMock(aiohttp.ClientResponse), "Arbitrary API error")
+        attachment = MockAttachment(to_file=AsyncMock(side_effect=arbitrary_error))
+
+        with self.assertLogs(logger=incidents.log, level=logging.ERROR):
+            acquired_file = await incidents.download_file(attachment)
+
+        self.assertIsNone(acquired_file)
+
+
+class TestMakeEmbed(unittest.IsolatedAsyncioTestCase):
+    """Collection of tests for the `make_embed` helper function."""
+
+    async def test_make_embed_actioned(self):
+        """Embed is coloured green and footer contains 'Actioned' when `outcome=Signal.ACTIONED`."""
+        embed, file = await incidents.make_embed(MockMessage(), incidents.Signal.ACTIONED, MockMember())
+
+        self.assertEqual(embed.colour.value, Colours.soft_green)
+        self.assertIn("Actioned", embed.footer.text)
+
+    async def test_make_embed_not_actioned(self):
+        """Embed is coloured red and footer contains 'Rejected' when `outcome=Signal.NOT_ACTIONED`."""
+        embed, file = await incidents.make_embed(MockMessage(), incidents.Signal.NOT_ACTIONED, MockMember())
+
+        self.assertEqual(embed.colour.value, Colours.soft_red)
+        self.assertIn("Rejected", embed.footer.text)
+
+    async def test_make_embed_content(self):
+        """Incident content appears as embed description."""
+        incident = MockMessage(content="this is an incident")
+        embed, file = await incidents.make_embed(incident, incidents.Signal.ACTIONED, MockMember())
+
+        self.assertEqual(incident.content, embed.description)
+
+    async def test_make_embed_with_attachment_succeeds(self):
+        """Incident's attachment is downloaded and displayed in the embed's image field."""
+        file = MagicMock(discord.File, filename="bigbadjoe.jpg")
+        attachment = MockAttachment(filename="bigbadjoe.jpg")
+        incident = MockMessage(content="this is an incident", attachments=[attachment])
+
+        # Patch `download_file` to return our `file`
+        with patch("bot.exts.moderation.incidents.download_file", AsyncMock(return_value=file)):
+            embed, returned_file = await incidents.make_embed(incident, incidents.Signal.ACTIONED, MockMember())
+
+        self.assertIs(file, returned_file)
+        self.assertEqual("attachment://bigbadjoe.jpg", embed.image.url)
+
+    async def test_make_embed_with_attachment_fails(self):
+        """Incident's attachment fails to download, proxy url is linked instead."""
+        attachment = MockAttachment(proxy_url="discord.com/bigbadjoe.jpg")
+        incident = MockMessage(content="this is an incident", attachments=[attachment])
+
+        # Patch `download_file` to return None as if the download failed
+        with patch("bot.exts.moderation.incidents.download_file", AsyncMock(return_value=None)):
+            embed, returned_file = await incidents.make_embed(incident, incidents.Signal.ACTIONED, MockMember())
+
+        self.assertIsNone(returned_file)
+
+        # The author name field is simply expected to have something in it, we do not assert the message
+        self.assertGreater(len(embed.author.name), 0)
+        self.assertEqual(embed.author.url, "discord.com/bigbadjoe.jpg")  # However, it should link the exact url
+
+
+@patch("bot.constants.Channels.incidents", 123)
+class TestIsIncident(unittest.TestCase):
+    """
+    Collection of tests for the `is_incident` helper function.
+
+    In `setUp`, we will create a mock message which should qualify as an incident. Each
+    test case will then mutate this instance to make it **not** qualify, in various ways.
+
+    Notice that we patch the #incidents channel id globally for this class.
+    """
+
+    def setUp(self) -> None:
+        """Prepare a mock message which should qualify as an incident."""
+        self.incident = MockMessage(
+            channel=MockTextChannel(id=123),
+            content="this is an incident",
+            author=MockUser(bot=False),
+            pinned=False,
+        )
+
+    def test_is_incident_true(self):
+        """Message qualifies as an incident if unchanged."""
+        self.assertTrue(incidents.is_incident(self.incident))
+
+    def check_false(self):
+        """Assert that `self.incident` does **not** qualify as an incident."""
+        self.assertFalse(incidents.is_incident(self.incident))
+
+    def test_is_incident_false_channel(self):
+        """Message doesn't qualify if sent outside of #incidents."""
+        self.incident.channel = MockTextChannel(id=456)
+        self.check_false()
+
+    def test_is_incident_false_content(self):
+        """Message doesn't qualify if content begins with hash symbol."""
+        self.incident.content = "# this is a comment message"
+        self.check_false()
+
+    def test_is_incident_false_author(self):
+        """Message doesn't qualify if author is a bot."""
+        self.incident.author = MockUser(bot=True)
+        self.check_false()
+
+    def test_is_incident_false_pinned(self):
+        """Message doesn't qualify if it is pinned."""
+        self.incident.pinned = True
+        self.check_false()
+
+
+class TestOwnReactions(unittest.TestCase):
+    """Assertions for the `own_reactions` function."""
+
+    def test_own_reactions(self):
+        """Only bot's own emoji are extracted from the input incident."""
+        reactions = (
+            MockReaction(emoji="A", me=True),
+            MockReaction(emoji="B", me=True),
+            MockReaction(emoji="C", me=False),
+        )
+        message = MockMessage(reactions=reactions)
+        self.assertSetEqual(incidents.own_reactions(message), {"A", "B"})
+
+
+@patch("bot.exts.moderation.incidents.ALL_SIGNALS", {"A", "B"})
+class TestHasSignals(unittest.TestCase):
+    """
+    Assertions for the `has_signals` function.
+
+    We patch `ALL_SIGNALS` globally. Each test function then patches `own_reactions`
+    as appropriate.
+    """
+
+    def test_has_signals_true(self):
+        """True when `own_reactions` returns all emoji in `ALL_SIGNALS`."""
+        message = MockMessage()
+        own_reactions = MagicMock(return_value={"A", "B"})
+
+        with patch("bot.exts.moderation.incidents.own_reactions", own_reactions):
+            self.assertTrue(incidents.has_signals(message))
+
+    def test_has_signals_false(self):
+        """False when `own_reactions` does not return all emoji in `ALL_SIGNALS`."""
+        message = MockMessage()
+        own_reactions = MagicMock(return_value={"A", "C"})
+
+        with patch("bot.exts.moderation.incidents.own_reactions", own_reactions):
+            self.assertFalse(incidents.has_signals(message))
+
+
+@patch("bot.exts.moderation.incidents.Signal", MockSignal)
+class TestAddSignals(unittest.IsolatedAsyncioTestCase):
+    """
+    Assertions for the `add_signals` coroutine.
+
+    These are all fairly similar and could go into a single test function, but I found the
+    patching & sub-testing fairly awkward in that case and decided to split them up
+    to avoid unnecessary syntax noise.
+    """
+
+    def setUp(self):
+        """Prepare a mock incident message for tests to use."""
+        self.incident = MockMessage()
+
+    @patch("bot.exts.moderation.incidents.own_reactions", MagicMock(return_value=set()))
+    async def test_add_signals_missing(self):
+        """All emoji are added when none are present."""
+        await incidents.add_signals(self.incident)
+        self.incident.add_reaction.assert_has_calls([call("A"), call("B")])
+
+    @patch("bot.exts.moderation.incidents.own_reactions", MagicMock(return_value={"A"}))
+    async def test_add_signals_partial(self):
+        """Only missing emoji are added when some are present."""
+        await incidents.add_signals(self.incident)
+        self.incident.add_reaction.assert_has_calls([call("B")])
+
+    @patch("bot.exts.moderation.incidents.own_reactions", MagicMock(return_value={"A", "B"}))
+    async def test_add_signals_present(self):
+        """No emoji are added when all are present."""
+        await incidents.add_signals(self.incident)
+        self.incident.add_reaction.assert_not_called()
+
+
+class TestIncidents(unittest.IsolatedAsyncioTestCase):
+    """
+    Tests for bound methods of the `Incidents` cog.
+
+    Use this as a base class for `Incidents` tests - it will prepare a fresh instance
+    for each test function, but not make any assertions on its own. Tests can mutate
+    the instance as they wish.
+    """
+
+    def setUp(self):
+        """
+        Prepare a fresh `Incidents` instance for each test.
+
+        Note that this will not schedule `crawl_incidents` in the background, as everything
+        is being mocked. The `crawl_task` attribute will end up being None.
+        """
+        self.cog_instance = incidents.Incidents(MockBot())
+
+
+@patch("asyncio.sleep", AsyncMock())  # Prevent the coro from sleeping to speed up the test
+class TestCrawlIncidents(TestIncidents):
+    """
+    Tests for the `Incidents.crawl_incidents` coroutine.
+
+    Apart from `test_crawl_incidents_waits_until_cache_ready`, all tests in this class
+    will patch the return values of `is_incident` and `has_signal` and then observe
+    whether the `AsyncMock` for `add_signals` was awaited or not.
+
+    The `add_signals` mock is added by each test separately to ensure it is clean (has not
+    been awaited by another test yet). The mock can be reset, but this appears to be the
+    cleaner way.
+
+    For each test, we inject a mock channel with a history of 1 message only (see: `setUp`).
+    """
+
+    def setUp(self):
+        """For each test, ensure `bot.get_channel` returns a channel with 1 arbitrary message."""
+        super().setUp()  # First ensure we get `cog_instance` from parent
+
+        incidents_history = MagicMock(return_value=MockAsyncIterable([MockMessage()]))
+        self.cog_instance.bot.get_channel = MagicMock(return_value=MockTextChannel(history=incidents_history))
+
+    async def test_crawl_incidents_waits_until_cache_ready(self):
+        """
+        The coroutine will await the `wait_until_guild_available` event.
+
+        Since this task is schedule in the `__init__`, it is critical that it waits for the
+        cache to be ready, so that it can safely get the #incidents channel.
+        """
+        await self.cog_instance.crawl_incidents()
+        self.cog_instance.bot.wait_until_guild_available.assert_awaited()
+
+    @patch("bot.exts.moderation.incidents.add_signals", AsyncMock())
+    @patch("bot.exts.moderation.incidents.is_incident", MagicMock(return_value=False))  # Message doesn't qualify
+    @patch("bot.exts.moderation.incidents.has_signals", MagicMock(return_value=False))
+    async def test_crawl_incidents_noop_if_is_not_incident(self):
+        """Signals are not added for a non-incident message."""
+        await self.cog_instance.crawl_incidents()
+        incidents.add_signals.assert_not_awaited()
+
+    @patch("bot.exts.moderation.incidents.add_signals", AsyncMock())
+    @patch("bot.exts.moderation.incidents.is_incident", MagicMock(return_value=True))  # Message qualifies
+    @patch("bot.exts.moderation.incidents.has_signals", MagicMock(return_value=True))  # But already has signals
+    async def test_crawl_incidents_noop_if_message_already_has_signals(self):
+        """Signals are not added for messages which already have them."""
+        await self.cog_instance.crawl_incidents()
+        incidents.add_signals.assert_not_awaited()
+
+    @patch("bot.exts.moderation.incidents.add_signals", AsyncMock())
+    @patch("bot.exts.moderation.incidents.is_incident", MagicMock(return_value=True))  # Message qualifies
+    @patch("bot.exts.moderation.incidents.has_signals", MagicMock(return_value=False))  # And doesn't have signals
+    async def test_crawl_incidents_add_signals_called(self):
+        """Message has signals added as it does not have them yet and qualifies as an incident."""
+        await self.cog_instance.crawl_incidents()
+        incidents.add_signals.assert_awaited_once()
+
+
+class TestArchive(TestIncidents):
+    """Tests for the `Incidents.archive` coroutine."""
+
+    async def test_archive_webhook_not_found(self):
+        """
+        Method recovers and returns False when the webhook is not found.
+
+        Implicitly, this also tests that the error is handled internally and doesn't
+        propagate out of the method, which is just as important.
+        """
+        self.cog_instance.bot.fetch_webhook = AsyncMock(side_effect=mock_404)
+        self.assertFalse(
+            await self.cog_instance.archive(incident=MockMessage(), outcome=MagicMock(), actioned_by=MockMember())
+        )
+
+    async def test_archive_relays_incident(self):
+        """
+        If webhook is found, method relays `incident` properly.
+
+        This test will assert that the fetched webhook's `send` method is fed the correct arguments,
+        and that the `archive` method returns True.
+        """
+        webhook = MockAsyncWebhook()
+        self.cog_instance.bot.fetch_webhook = AsyncMock(return_value=webhook)  # Patch in our webhook
+
+        # Define our own `incident` to be archived
+        incident = MockMessage(
+            content="this is an incident",
+            author=MockUser(name="author_name", avatar_url="author_avatar"),
+            id=123,
+        )
+        built_embed = MagicMock(discord.Embed, id=123)  # We patch `make_embed` to return this
+
+        with patch("bot.exts.moderation.incidents.make_embed", AsyncMock(return_value=(built_embed, None))):
+            archive_return = await self.cog_instance.archive(incident, MagicMock(value="A"), MockMember())
+
+        # Now we check that the webhook was given the correct args, and that `archive` returned True
+        webhook.send.assert_called_once_with(
+            embed=built_embed,
+            username="author_name",
+            avatar_url="author_avatar",
+            file=None,
+        )
+        self.assertTrue(archive_return)
+
+    async def test_archive_clyde_username(self):
+        """
+        The archive webhook username is cleansed using `sub_clyde`.
+
+        Discord will reject any webhook with "clyde" in the username field, as it impersonates
+        the official Clyde bot. Since we do not control what the username will be (the incident
+        author name is used), we must ensure the name is cleansed, otherwise the relay may fail.
+
+        This test assumes the username is passed as a kwarg. If this test fails, please review
+        whether the passed argument is being retrieved correctly.
+        """
+        webhook = MockAsyncWebhook()
+        self.cog_instance.bot.fetch_webhook = AsyncMock(return_value=webhook)
+
+        message_from_clyde = MockMessage(author=MockUser(name="clyde the great"))
+        await self.cog_instance.archive(message_from_clyde, MagicMock(incidents.Signal), MockMember())
+
+        self.assertNotIn("clyde", webhook.send.call_args.kwargs["username"])
+
+
+class TestMakeConfirmationTask(TestIncidents):
+    """
+    Tests for the `Incidents.make_confirmation_task` method.
+
+    Writing tests for this method is difficult, as it mostly just delegates the provided
+    information elsewhere. There is very little internal logic. Whether our approach
+    works conceptually is difficult to prove using unit tests.
+    """
+
+    def test_make_confirmation_task_check(self):
+        """
+        The internal check will recognize the passed incident.
+
+        This is a little tricky - we first pass a message with a specific `id` in, and then
+        retrieve the built check from the `call_args` of the `wait_for` method. This relies
+        on the check being passed as a kwarg.
+
+        Once the check is retrieved, we assert that it gives True for our incident's `id`,
+        and False for any other.
+
+        If this function begins to fail, first check that `created_check` is being retrieved
+        correctly. It should be the function that is built locally in the tested method.
+        """
+        self.cog_instance.make_confirmation_task(MockMessage(id=123))
+
+        self.cog_instance.bot.wait_for.assert_called_once()
+        created_check = self.cog_instance.bot.wait_for.call_args.kwargs["check"]
+
+        # The `message_id` matches the `id` of our incident
+        self.assertTrue(created_check(payload=MagicMock(message_id=123)))
+
+        # This `message_id` does not match
+        self.assertFalse(created_check(payload=MagicMock(message_id=0)))
+
+
+@patch("bot.exts.moderation.incidents.ALLOWED_ROLES", {1, 2})
+@patch("bot.exts.moderation.incidents.Incidents.make_confirmation_task", AsyncMock())  # Generic awaitable
+class TestProcessEvent(TestIncidents):
+    """Tests for the `Incidents.process_event` coroutine."""
+
+    async def test_process_event_bad_role(self):
+        """The reaction is removed when the author lacks all allowed roles."""
+        incident = MockMessage()
+        member = MockMember(roles=[MockRole(id=0)])  # Must have role 1 or 2
+
+        await self.cog_instance.process_event("reaction", incident, member)
+        incident.remove_reaction.assert_called_once_with("reaction", member)
+
+    async def test_process_event_bad_emoji(self):
+        """
+        The reaction is removed when an invalid emoji is used.
+
+        This requires that we pass in a `member` with valid roles, as we need the role check
+        to succeed.
+        """
+        incident = MockMessage()
+        member = MockMember(roles=[MockRole(id=1)])  # Member has allowed role
+
+        await self.cog_instance.process_event("invalid_signal", incident, member)
+        incident.remove_reaction.assert_called_once_with("invalid_signal", member)
+
+    async def test_process_event_no_archive_on_investigating(self):
+        """Message is not archived on `Signal.INVESTIGATING`."""
+        with patch("bot.exts.moderation.incidents.Incidents.archive", AsyncMock()) as mocked_archive:
+            await self.cog_instance.process_event(
+                reaction=incidents.Signal.INVESTIGATING.value,
+                incident=MockMessage(),
+                member=MockMember(roles=[MockRole(id=1)]),
+            )
+
+        mocked_archive.assert_not_called()
+
+    async def test_process_event_no_delete_if_archive_fails(self):
+        """
+        Original message is not deleted when `Incidents.archive` returns False.
+
+        This is the way of signaling that the relay failed, and we should not remove the original,
+        as that would result in losing the incident record.
+        """
+        incident = MockMessage()
+
+        with patch("bot.exts.moderation.incidents.Incidents.archive", AsyncMock(return_value=False)):
+            await self.cog_instance.process_event(
+                reaction=incidents.Signal.ACTIONED.value,
+                incident=incident,
+                member=MockMember(roles=[MockRole(id=1)])
+            )
+
+        incident.delete.assert_not_called()
+
+    async def test_process_event_confirmation_task_is_awaited(self):
+        """Task given by `Incidents.make_confirmation_task` is awaited before method exits."""
+        mock_task = AsyncMock()
+
+        with patch("bot.exts.moderation.incidents.Incidents.make_confirmation_task", mock_task):
+            await self.cog_instance.process_event(
+                reaction=incidents.Signal.ACTIONED.value,
+                incident=MockMessage(),
+                member=MockMember(roles=[MockRole(id=1)])
+            )
+
+        mock_task.assert_awaited()
+
+    async def test_process_event_confirmation_task_timeout_is_handled(self):
+        """
+        Confirmation task `asyncio.TimeoutError` is handled gracefully.
+
+        We have `make_confirmation_task` return a mock with a side effect, and then catch the
+        exception should it propagate out of `process_event`. This is so that we can then manually
+        fail the test with a more informative message than just the plain traceback.
+        """
+        mock_task = AsyncMock(side_effect=asyncio.TimeoutError())
+
+        try:
+            with patch("bot.exts.moderation.incidents.Incidents.make_confirmation_task", mock_task):
+                await self.cog_instance.process_event(
+                    reaction=incidents.Signal.ACTIONED.value,
+                    incident=MockMessage(),
+                    member=MockMember(roles=[MockRole(id=1)])
+                )
+        except asyncio.TimeoutError:
+            self.fail("TimeoutError was not handled gracefully, and propagated out of `process_event`!")
+
+
+class TestResolveMessage(TestIncidents):
+    """Tests for the `Incidents.resolve_message` coroutine."""
+
+    async def test_resolve_message_pass_message_id(self):
+        """Method will call `_get_message` with the passed `message_id`."""
+        await self.cog_instance.resolve_message(123)
+        self.cog_instance.bot._connection._get_message.assert_called_once_with(123)
+
+    async def test_resolve_message_in_cache(self):
+        """
+        No API call is made if the queried message exists in the cache.
+
+        We mock the `_get_message` return value regardless of input. Whether it finds the message
+        internally is considered d.py's responsibility, not ours.
+        """
+        cached_message = MockMessage(id=123)
+        self.cog_instance.bot._connection._get_message = MagicMock(return_value=cached_message)
+
+        return_value = await self.cog_instance.resolve_message(123)
+
+        self.assertIs(return_value, cached_message)
+        self.cog_instance.bot.get_channel.assert_not_called()  # The `fetch_message` line was never hit
+
+    async def test_resolve_message_not_in_cache(self):
+        """
+        The message is retrieved from the API if it isn't cached.
+
+        This is desired behaviour for messages which exist, but were sent before the bot's
+        current session.
+        """
+        self.cog_instance.bot._connection._get_message = MagicMock(return_value=None)  # Cache returns None
+
+        # API returns our message
+        uncached_message = MockMessage()
+        fetch_message = AsyncMock(return_value=uncached_message)
+        self.cog_instance.bot.get_channel = MagicMock(return_value=MockTextChannel(fetch_message=fetch_message))
+
+        retrieved_message = await self.cog_instance.resolve_message(123)
+        self.assertIs(retrieved_message, uncached_message)
+
+    async def test_resolve_message_doesnt_exist(self):
+        """
+        If the API returns a 404, the function handles it gracefully and returns None.
+
+        This is an edge-case happening with racing events - event A will relay the message
+        to the archive and delete the original. Once event B acquires the `event_lock`,
+        it will not find the message in the cache, and will ask the API.
+        """
+        self.cog_instance.bot._connection._get_message = MagicMock(return_value=None)  # Cache returns None
+
+        fetch_message = AsyncMock(side_effect=mock_404)
+        self.cog_instance.bot.get_channel = MagicMock(return_value=MockTextChannel(fetch_message=fetch_message))
+
+        self.assertIsNone(await self.cog_instance.resolve_message(123))
+
+    async def test_resolve_message_fetch_fails(self):
+        """
+        Non-404 errors are handled, logged & None is returned.
+
+        In contrast with a 404, this should make an error-level log. We assert that at least
+        one such log was made - we do not make any assertions about the log's message.
+        """
+        self.cog_instance.bot._connection._get_message = MagicMock(return_value=None)  # Cache returns None
+
+        arbitrary_error = discord.HTTPException(
+            response=MagicMock(aiohttp.ClientResponse),
+            message="Arbitrary error",
+        )
+        fetch_message = AsyncMock(side_effect=arbitrary_error)
+        self.cog_instance.bot.get_channel = MagicMock(return_value=MockTextChannel(fetch_message=fetch_message))
+
+        with self.assertLogs(logger=incidents.log, level=logging.ERROR):
+            self.assertIsNone(await self.cog_instance.resolve_message(123))
+
+
+@patch("bot.constants.Channels.incidents", 123)
+class TestOnRawReactionAdd(TestIncidents):
+    """
+    Tests for the `Incidents.on_raw_reaction_add` listener.
+
+    Writing tests for this listener comes with additional complexity due to the listener
+    awaiting the `crawl_task` task. See `asyncSetUp` for further details, which attempts
+    to make unit testing this function possible.
+    """
+
+    def setUp(self):
+        """
+        Prepare & assign `payload` attribute.
+
+        This attribute represents an *ideal* payload which will not be rejected by the
+        listener. As each test will receive a fresh instance, it can be mutated to
+        observe how the listener's behaviour changes with different attributes on
+        the passed payload.
+        """
+        super().setUp()  # Ensure `cog_instance` is assigned
+
+        self.payload = MagicMock(
+            discord.RawReactionActionEvent,
+            channel_id=123,  # Patched at class level
+            message_id=456,
+            member=MockMember(bot=False),
+            emoji="reaction",
+        )
+
+    async def asyncSetUp(self):  # noqa: N802
+        """
+        Prepare an empty task and assign it as `crawl_task`.
+
+        It appears that the `unittest` framework does not provide anything for mocking
+        asyncio tasks. An `AsyncMock` instance can be called and then awaited, however,
+        it does not provide the `done` method or any other parts of the `asyncio.Task`
+        interface.
+
+        Although we do not need to make any assertions about the task itself while
+        testing the listener, the code will still await it and call the `done` method,
+        and so we must inject something that will not fail on either action.
+
+        Note that this is done in an `asyncSetUp`, which runs after `setUp`.
+        The justification is that creating an actual task requires the event
+        loop to be ready, which is not the case in the `setUp`.
+        """
+        mock_task = asyncio.create_task(AsyncMock()())  # Mock async func, then a coro
+        self.cog_instance.crawl_task = mock_task
+
+    async def test_on_raw_reaction_add_wrong_channel(self):
+        """
+        Events outside of #incidents will be ignored.
+
+        We check this by asserting that `resolve_message` was never queried.
+        """
+        self.payload.channel_id = 0
+        self.cog_instance.resolve_message = AsyncMock()
+
+        await self.cog_instance.on_raw_reaction_add(self.payload)
+        self.cog_instance.resolve_message.assert_not_called()
+
+    async def test_on_raw_reaction_add_user_is_bot(self):
+        """
+        Events dispatched by bot accounts will be ignored.
+
+        We check this by asserting that `resolve_message` was never queried.
+        """
+        self.payload.member = MockMember(bot=True)
+        self.cog_instance.resolve_message = AsyncMock()
+
+        await self.cog_instance.on_raw_reaction_add(self.payload)
+        self.cog_instance.resolve_message.assert_not_called()
+
+    async def test_on_raw_reaction_add_message_doesnt_exist(self):
+        """
+        Listener gracefully handles the case where `resolve_message` gives None.
+
+        We check this by asserting that `process_event` was never called.
+        """
+        self.cog_instance.process_event = AsyncMock()
+        self.cog_instance.resolve_message = AsyncMock(return_value=None)
+
+        await self.cog_instance.on_raw_reaction_add(self.payload)
+        self.cog_instance.process_event.assert_not_called()
+
+    async def test_on_raw_reaction_add_message_is_not_an_incident(self):
+        """
+        The event won't be processed if the related message is not an incident.
+
+        This is an edge-case that can happen if someone manually leaves a reaction
+        on a pinned message, or a comment.
+
+        We check this by asserting that `process_event` was never called.
+        """
+        self.cog_instance.process_event = AsyncMock()
+        self.cog_instance.resolve_message = AsyncMock(return_value=MockMessage())
+
+        with patch("bot.exts.moderation.incidents.is_incident", MagicMock(return_value=False)):
+            await self.cog_instance.on_raw_reaction_add(self.payload)
+
+        self.cog_instance.process_event.assert_not_called()
+
+    async def test_on_raw_reaction_add_valid_event_is_processed(self):
+        """
+        If the reaction event is valid, it is passed to `process_event`.
+
+        This is the case when everything goes right:
+            * The reaction was placed in #incidents, and not by a bot
+            * The message was found successfully
+            * The message qualifies as an incident
+
+        Additionally, we check that all arguments were passed as expected.
+        """
+        incident = MockMessage(id=1)
+
+        self.cog_instance.process_event = AsyncMock()
+        self.cog_instance.resolve_message = AsyncMock(return_value=incident)
+
+        with patch("bot.exts.moderation.incidents.is_incident", MagicMock(return_value=True)):
+            await self.cog_instance.on_raw_reaction_add(self.payload)
+
+        self.cog_instance.process_event.assert_called_with(
+            "reaction",  # Defined in `self.payload`
+            incident,
+            self.payload.member,
+        )
+
+
+class TestOnMessage(TestIncidents):
+    """
+    Tests for the `Incidents.on_message` listener.
+
+    Notice the decorators mocking the `is_incident` return value. The `is_incidents`
+    function is tested in `TestIsIncident` - here we do not worry about it.
+    """
+
+    @patch("bot.exts.moderation.incidents.is_incident", MagicMock(return_value=True))
+    async def test_on_message_incident(self):
+        """Messages qualifying as incidents are passed to `add_signals`."""
+        incident = MockMessage()
+
+        with patch("bot.exts.moderation.incidents.add_signals", AsyncMock()) as mock_add_signals:
+            await self.cog_instance.on_message(incident)
+
+        mock_add_signals.assert_called_once_with(incident)
+
+    @patch("bot.exts.moderation.incidents.is_incident", MagicMock(return_value=False))
+    async def test_on_message_non_incident(self):
+        """Messages not qualifying as incidents are ignored."""
+        with patch("bot.exts.moderation.incidents.add_signals", AsyncMock()) as mock_add_signals:
+            await self.cog_instance.on_message(MockMessage())
+
+        mock_add_signals.assert_not_called()
diff --git a/tests/bot/exts/moderation/test_modlog.py b/tests/bot/exts/moderation/test_modlog.py
new file mode 100644
index 000000000..f8f142484
--- /dev/null
+++ b/tests/bot/exts/moderation/test_modlog.py
@@ -0,0 +1,29 @@
+import unittest
+
+import discord
+
+from bot.exts.moderation.modlog import ModLog
+from tests.helpers import MockBot, MockTextChannel
+
+
+class ModLogTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for moderation logs."""
+
+    def setUp(self):
+        self.bot = MockBot()
+        self.cog = ModLog(self.bot)
+        self.channel = MockTextChannel()
+
+    async def test_log_entry_description_truncation(self):
+        """Test that embed description for ModLog entry is truncated."""
+        self.bot.get_channel.return_value = self.channel
+        await self.cog.send_log_message(
+            icon_url="foo",
+            colour=discord.Colour.blue(),
+            title="bar",
+            text="foo bar" * 3000
+        )
+        embed = self.channel.send.call_args[1]["embed"]
+        self.assertEqual(
+            embed.description, ("foo bar" * 3000)[:2045] + "..."
+        )
diff --git a/tests/bot/exts/moderation/test_silence.py b/tests/bot/exts/moderation/test_silence.py
new file mode 100644
index 000000000..fa5fc9e81
--- /dev/null
+++ b/tests/bot/exts/moderation/test_silence.py
@@ -0,0 +1,493 @@
+import asyncio
+import unittest
+from datetime import datetime, timezone
+from unittest import mock
+from unittest.mock import Mock
+
+from async_rediscache import RedisSession
+from discord import PermissionOverwrite
+
+from bot.constants import Channels, Guild, Roles
+from bot.exts.moderation import silence
+from tests.helpers import MockBot, MockContext, MockTextChannel, autospec
+
+redis_session = None
+redis_loop = asyncio.get_event_loop()
+
+
+def setUpModule():  # noqa: N802
+    """Create and connect to the fakeredis session."""
+    global redis_session
+    redis_session = RedisSession(use_fakeredis=True)
+    redis_loop.run_until_complete(redis_session.connect())
+
+
+def tearDownModule():  # noqa: N802
+    """Close the fakeredis session."""
+    if redis_session:
+        redis_loop.run_until_complete(redis_session.close())
+
+
+# Have to subclass it because builtins can't be patched.
+class PatchedDatetime(datetime):
+    """A datetime object with a mocked now() function."""
+
+    now = mock.create_autospec(datetime, "now")
+
+
+class SilenceNotifierTests(unittest.IsolatedAsyncioTestCase):
+    def setUp(self) -> None:
+        self.alert_channel = MockTextChannel()
+        self.notifier = silence.SilenceNotifier(self.alert_channel)
+        self.notifier.stop = self.notifier_stop_mock = Mock()
+        self.notifier.start = self.notifier_start_mock = Mock()
+
+    def test_add_channel_adds_channel(self):
+        """Channel is added to `_silenced_channels` with the current loop."""
+        channel = Mock()
+        with mock.patch.object(self.notifier, "_silenced_channels") as silenced_channels:
+            self.notifier.add_channel(channel)
+        silenced_channels.__setitem__.assert_called_with(channel, self.notifier._current_loop)
+
+    def test_add_channel_starts_loop(self):
+        """Loop is started if `_silenced_channels` was empty."""
+        self.notifier.add_channel(Mock())
+        self.notifier_start_mock.assert_called_once()
+
+    def test_add_channel_skips_start_with_channels(self):
+        """Loop start is not called when `_silenced_channels` is not empty."""
+        with mock.patch.object(self.notifier, "_silenced_channels"):
+            self.notifier.add_channel(Mock())
+        self.notifier_start_mock.assert_not_called()
+
+    def test_remove_channel_removes_channel(self):
+        """Channel is removed from `_silenced_channels`."""
+        channel = Mock()
+        with mock.patch.object(self.notifier, "_silenced_channels") as silenced_channels:
+            self.notifier.remove_channel(channel)
+        silenced_channels.__delitem__.assert_called_with(channel)
+
+    def test_remove_channel_stops_loop(self):
+        """Notifier loop is stopped if `_silenced_channels` is empty after remove."""
+        with mock.patch.object(self.notifier, "_silenced_channels", __bool__=lambda _: False):
+            self.notifier.remove_channel(Mock())
+        self.notifier_stop_mock.assert_called_once()
+
+    def test_remove_channel_skips_stop_with_channels(self):
+        """Notifier loop is not stopped if `_silenced_channels` is not empty after remove."""
+        self.notifier.remove_channel(Mock())
+        self.notifier_stop_mock.assert_not_called()
+
+    async def test_notifier_private_sends_alert(self):
+        """Alert is sent on 15 min intervals."""
+        test_cases = (900, 1800, 2700)
+        for current_loop in test_cases:
+            with self.subTest(current_loop=current_loop):
+                with mock.patch.object(self.notifier, "_current_loop", new=current_loop):
+                    await self.notifier._notifier()
+                self.alert_channel.send.assert_called_once_with(
+                    f"<@&{Roles.moderators}> currently silenced channels: "
+                )
+            self.alert_channel.send.reset_mock()
+
+    async def test_notifier_skips_alert(self):
+        """Alert is skipped on first loop or not an increment of 900."""
+        test_cases = (0, 15, 5000)
+        for current_loop in test_cases:
+            with self.subTest(current_loop=current_loop):
+                with mock.patch.object(self.notifier, "_current_loop", new=current_loop):
+                    await self.notifier._notifier()
+                    self.alert_channel.send.assert_not_called()
+
+
+@autospec(silence.Silence, "previous_overwrites", "unsilence_timestamps", pass_mocks=False)
+class SilenceCogTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for the general functionality of the Silence cog."""
+
+    @autospec(silence, "Scheduler", pass_mocks=False)
+    def setUp(self) -> None:
+        self.bot = MockBot()
+        self.cog = silence.Silence(self.bot)
+
+    @autospec(silence, "SilenceNotifier", pass_mocks=False)
+    async def test_async_init_got_guild(self):
+        """Bot got guild after it became available."""
+        await self.cog._async_init()
+        self.bot.wait_until_guild_available.assert_awaited_once()
+        self.bot.get_guild.assert_called_once_with(Guild.id)
+
+    @autospec(silence, "SilenceNotifier", pass_mocks=False)
+    async def test_async_init_got_channels(self):
+        """Got channels from bot."""
+        self.bot.get_channel.side_effect = lambda id_: MockTextChannel(id=id_)
+
+        await self.cog._async_init()
+        self.assertEqual(self.cog._mod_alerts_channel.id, Channels.mod_alerts)
+
+    @autospec(silence, "SilenceNotifier")
+    async def test_async_init_got_notifier(self, notifier):
+        """Notifier was started with channel."""
+        self.bot.get_channel.side_effect = lambda id_: MockTextChannel(id=id_)
+
+        await self.cog._async_init()
+        notifier.assert_called_once_with(MockTextChannel(id=Channels.mod_log))
+        self.assertEqual(self.cog.notifier, notifier.return_value)
+
+    @autospec(silence, "SilenceNotifier", pass_mocks=False)
+    async def test_async_init_rescheduled(self):
+        """`_reschedule_` coroutine was awaited."""
+        self.cog._reschedule = mock.create_autospec(self.cog._reschedule)
+        await self.cog._async_init()
+        self.cog._reschedule.assert_awaited_once_with()
+
+    def test_cog_unload_cancelled_tasks(self):
+        """The init task was cancelled."""
+        self.cog._init_task = asyncio.Future()
+        self.cog.cog_unload()
+
+        # It's too annoying to test cancel_all since it's a done callback and wrapped in a lambda.
+        self.assertTrue(self.cog._init_task.cancelled())
+
+    @autospec("discord.ext.commands", "has_any_role")
+    @mock.patch.object(silence, "MODERATION_ROLES", new=(1, 2, 3))
+    async def test_cog_check(self, role_check):
+        """Role check was called with `MODERATION_ROLES`"""
+        ctx = MockContext()
+        role_check.return_value.predicate = mock.AsyncMock()
+
+        await self.cog.cog_check(ctx)
+        role_check.assert_called_once_with(*(1, 2, 3))
+        role_check.return_value.predicate.assert_awaited_once_with(ctx)
+
+
+@autospec(silence.Silence, "previous_overwrites", "unsilence_timestamps", pass_mocks=False)
+class RescheduleTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for the rescheduling of cached unsilences."""
+
+    @autospec(silence, "Scheduler", "SilenceNotifier", pass_mocks=False)
+    def setUp(self):
+        self.bot = MockBot()
+        self.cog = silence.Silence(self.bot)
+        self.cog._unsilence_wrapper = mock.create_autospec(self.cog._unsilence_wrapper)
+
+        with mock.patch.object(self.cog, "_reschedule", autospec=True):
+            asyncio.run(self.cog._async_init())  # Populate instance attributes.
+
+    async def test_skipped_missing_channel(self):
+        """Did nothing because the channel couldn't be retrieved."""
+        self.cog.unsilence_timestamps.items.return_value = [(123, -1), (123, 1), (123, 10000000000)]
+        self.bot.get_channel.return_value = None
+
+        await self.cog._reschedule()
+
+        self.cog.notifier.add_channel.assert_not_called()
+        self.cog._unsilence_wrapper.assert_not_called()
+        self.cog.scheduler.schedule_later.assert_not_called()
+
+    async def test_added_permanent_to_notifier(self):
+        """Permanently silenced channels were added to the notifier."""
+        channels = [MockTextChannel(id=123), MockTextChannel(id=456)]
+        self.bot.get_channel.side_effect = channels
+        self.cog.unsilence_timestamps.items.return_value = [(123, -1), (456, -1)]
+
+        await self.cog._reschedule()
+
+        self.cog.notifier.add_channel.assert_any_call(channels[0])
+        self.cog.notifier.add_channel.assert_any_call(channels[1])
+
+        self.cog._unsilence_wrapper.assert_not_called()
+        self.cog.scheduler.schedule_later.assert_not_called()
+
+    async def test_unsilenced_expired(self):
+        """Unsilenced expired silences."""
+        channels = [MockTextChannel(id=123), MockTextChannel(id=456)]
+        self.bot.get_channel.side_effect = channels
+        self.cog.unsilence_timestamps.items.return_value = [(123, 100), (456, 200)]
+
+        await self.cog._reschedule()
+
+        self.cog._unsilence_wrapper.assert_any_call(channels[0])
+        self.cog._unsilence_wrapper.assert_any_call(channels[1])
+
+        self.cog.notifier.add_channel.assert_not_called()
+        self.cog.scheduler.schedule_later.assert_not_called()
+
+    @mock.patch.object(silence, "datetime", new=PatchedDatetime)
+    async def test_rescheduled_active(self):
+        """Rescheduled active silences."""
+        channels = [MockTextChannel(id=123), MockTextChannel(id=456)]
+        self.bot.get_channel.side_effect = channels
+        self.cog.unsilence_timestamps.items.return_value = [(123, 2000), (456, 3000)]
+        silence.datetime.now.return_value = datetime.fromtimestamp(1000, tz=timezone.utc)
+
+        self.cog._unsilence_wrapper = mock.MagicMock()
+        unsilence_return = self.cog._unsilence_wrapper.return_value
+
+        await self.cog._reschedule()
+
+        # Yuck.
+        calls = [mock.call(1000, 123, unsilence_return), mock.call(2000, 456, unsilence_return)]
+        self.cog.scheduler.schedule_later.assert_has_calls(calls)
+
+        unsilence_calls = [mock.call(channel) for channel in channels]
+        self.cog._unsilence_wrapper.assert_has_calls(unsilence_calls)
+
+        self.cog.notifier.add_channel.assert_not_called()
+
+
+@autospec(silence.Silence, "previous_overwrites", "unsilence_timestamps", pass_mocks=False)
+class SilenceTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for the silence command and its related helper methods."""
+
+    @autospec(silence.Silence, "_reschedule", pass_mocks=False)
+    @autospec(silence, "Scheduler", "SilenceNotifier", pass_mocks=False)
+    def setUp(self) -> None:
+        self.bot = MockBot()
+        self.cog = silence.Silence(self.bot)
+        self.cog._init_task = asyncio.Future()
+        self.cog._init_task.set_result(None)
+
+        # Avoid unawaited coroutine warnings.
+        self.cog.scheduler.schedule_later.side_effect = lambda delay, task_id, coro: coro.close()
+
+        asyncio.run(self.cog._async_init())  # Populate instance attributes.
+
+        self.channel = MockTextChannel()
+        self.overwrite = PermissionOverwrite(stream=True, send_messages=True, add_reactions=False)
+        self.channel.overwrites_for.return_value = self.overwrite
+
+    async def test_sent_correct_message(self):
+        """Appropriate failure/success message was sent by the command."""
+        test_cases = (
+            (0.0001, silence.MSG_SILENCE_SUCCESS.format(duration=0.0001), True,),
+            (None, silence.MSG_SILENCE_PERMANENT, True,),
+            (5, silence.MSG_SILENCE_FAIL, False,),
+        )
+        for duration, message, was_silenced in test_cases:
+            ctx = MockContext()
+            with mock.patch.object(self.cog, "_set_silence_overwrites", return_value=was_silenced):
+                with self.subTest(was_silenced=was_silenced, message=message, duration=duration):
+                    await self.cog.silence.callback(self.cog, ctx, duration)
+                    ctx.send.assert_called_once_with(message)
+
+    async def test_skipped_already_silenced(self):
+        """Permissions were not set and `False` was returned for an already silenced channel."""
+        subtests = (
+            (False, PermissionOverwrite(send_messages=False, add_reactions=False)),
+            (True, PermissionOverwrite(send_messages=True, add_reactions=True)),
+            (True, PermissionOverwrite(send_messages=False, add_reactions=False)),
+        )
+
+        for contains, overwrite in subtests:
+            with self.subTest(contains=contains, overwrite=overwrite):
+                self.cog.scheduler.__contains__.return_value = contains
+                channel = MockTextChannel()
+                channel.overwrites_for.return_value = overwrite
+
+                self.assertFalse(await self.cog._set_silence_overwrites(channel))
+                channel.set_permissions.assert_not_called()
+
+    async def test_silenced_channel(self):
+        """Channel had `send_message` and `add_reactions` permissions revoked for verified role."""
+        self.assertTrue(await self.cog._set_silence_overwrites(self.channel))
+        self.assertFalse(self.overwrite.send_messages)
+        self.assertFalse(self.overwrite.add_reactions)
+        self.channel.set_permissions.assert_awaited_once_with(
+            self.cog._everyone_role,
+            overwrite=self.overwrite
+        )
+
+    async def test_preserved_other_overwrites(self):
+        """Channel's other unrelated overwrites were not changed."""
+        prev_overwrite_dict = dict(self.overwrite)
+        await self.cog._set_silence_overwrites(self.channel)
+        new_overwrite_dict = dict(self.overwrite)
+
+        # Remove 'send_messages' & 'add_reactions' keys because they were changed by the method.
+        del prev_overwrite_dict['send_messages']
+        del prev_overwrite_dict['add_reactions']
+        del new_overwrite_dict['send_messages']
+        del new_overwrite_dict['add_reactions']
+
+        self.assertDictEqual(prev_overwrite_dict, new_overwrite_dict)
+
+    async def test_temp_not_added_to_notifier(self):
+        """Channel was not added to notifier if a duration was set for the silence."""
+        with mock.patch.object(self.cog, "_set_silence_overwrites", return_value=True):
+            await self.cog.silence.callback(self.cog, MockContext(), 15)
+            self.cog.notifier.add_channel.assert_not_called()
+
+    async def test_indefinite_added_to_notifier(self):
+        """Channel was added to notifier if a duration was not set for the silence."""
+        with mock.patch.object(self.cog, "_set_silence_overwrites", return_value=True):
+            await self.cog.silence.callback(self.cog, MockContext(), None)
+            self.cog.notifier.add_channel.assert_called_once()
+
+    async def test_silenced_not_added_to_notifier(self):
+        """Channel was not added to the notifier if it was already silenced."""
+        with mock.patch.object(self.cog, "_set_silence_overwrites", return_value=False):
+            await self.cog.silence.callback(self.cog, MockContext(), 15)
+            self.cog.notifier.add_channel.assert_not_called()
+
+    async def test_cached_previous_overwrites(self):
+        """Channel's previous overwrites were cached."""
+        overwrite_json = '{"send_messages": true, "add_reactions": false}'
+        await self.cog._set_silence_overwrites(self.channel)
+        self.cog.previous_overwrites.set.assert_called_once_with(self.channel.id, overwrite_json)
+
+    @autospec(silence, "datetime")
+    async def test_cached_unsilence_time(self, datetime_mock):
+        """The UTC POSIX timestamp for the unsilence was cached."""
+        now_timestamp = 100
+        duration = 15
+        timestamp = now_timestamp + duration * 60
+        datetime_mock.now.return_value = datetime.fromtimestamp(now_timestamp, tz=timezone.utc)
+
+        ctx = MockContext(channel=self.channel)
+        await self.cog.silence.callback(self.cog, ctx, duration)
+
+        self.cog.unsilence_timestamps.set.assert_awaited_once_with(ctx.channel.id, timestamp)
+        datetime_mock.now.assert_called_once_with(tz=timezone.utc)  # Ensure it's using an aware dt.
+
+    async def test_cached_indefinite_time(self):
+        """A value of -1 was cached for a permanent silence."""
+        ctx = MockContext(channel=self.channel)
+        await self.cog.silence.callback(self.cog, ctx, None)
+        self.cog.unsilence_timestamps.set.assert_awaited_once_with(ctx.channel.id, -1)
+
+    async def test_scheduled_task(self):
+        """An unsilence task was scheduled."""
+        ctx = MockContext(channel=self.channel, invoke=mock.MagicMock())
+
+        await self.cog.silence.callback(self.cog, ctx, 5)
+
+        args = (300, ctx.channel.id, ctx.invoke.return_value)
+        self.cog.scheduler.schedule_later.assert_called_once_with(*args)
+        ctx.invoke.assert_called_once_with(self.cog.unsilence)
+
+    async def test_permanent_not_scheduled(self):
+        """A task was not scheduled for a permanent silence."""
+        ctx = MockContext(channel=self.channel)
+        await self.cog.silence.callback(self.cog, ctx, None)
+        self.cog.scheduler.schedule_later.assert_not_called()
+
+
+@autospec(silence.Silence, "unsilence_timestamps", pass_mocks=False)
+class UnsilenceTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for the unsilence command and its related helper methods."""
+
+    @autospec(silence.Silence, "_reschedule", pass_mocks=False)
+    @autospec(silence, "Scheduler", "SilenceNotifier", pass_mocks=False)
+    def setUp(self) -> None:
+        self.bot = MockBot(get_channel=lambda _: MockTextChannel())
+        self.cog = silence.Silence(self.bot)
+        self.cog._init_task = asyncio.Future()
+        self.cog._init_task.set_result(None)
+
+        overwrites_cache = mock.create_autospec(self.cog.previous_overwrites, spec_set=True)
+        self.cog.previous_overwrites = overwrites_cache
+
+        asyncio.run(self.cog._async_init())  # Populate instance attributes.
+
+        self.cog.scheduler.__contains__.return_value = True
+        overwrites_cache.get.return_value = '{"send_messages": true, "add_reactions": false}'
+        self.channel = MockTextChannel()
+        self.overwrite = PermissionOverwrite(stream=True, send_messages=False, add_reactions=False)
+        self.channel.overwrites_for.return_value = self.overwrite
+
+    async def test_sent_correct_message(self):
+        """Appropriate failure/success message was sent by the command."""
+        unsilenced_overwrite = PermissionOverwrite(send_messages=True, add_reactions=True)
+        test_cases = (
+            (True, silence.MSG_UNSILENCE_SUCCESS, unsilenced_overwrite),
+            (False, silence.MSG_UNSILENCE_FAIL, unsilenced_overwrite),
+            (False, silence.MSG_UNSILENCE_MANUAL, self.overwrite),
+            (False, silence.MSG_UNSILENCE_MANUAL, PermissionOverwrite(send_messages=False)),
+            (False, silence.MSG_UNSILENCE_MANUAL, PermissionOverwrite(add_reactions=False)),
+        )
+        for was_unsilenced, message, overwrite in test_cases:
+            ctx = MockContext()
+            with self.subTest(was_unsilenced=was_unsilenced, message=message, overwrite=overwrite):
+                with mock.patch.object(self.cog, "_unsilence", return_value=was_unsilenced):
+                    ctx.channel.overwrites_for.return_value = overwrite
+                    await self.cog.unsilence.callback(self.cog, ctx)
+                    ctx.channel.send.assert_called_once_with(message)
+
+    async def test_skipped_already_unsilenced(self):
+        """Permissions were not set and `False` was returned for an already unsilenced channel."""
+        self.cog.scheduler.__contains__.return_value = False
+        self.cog.previous_overwrites.get.return_value = None
+        channel = MockTextChannel()
+
+        self.assertFalse(await self.cog._unsilence(channel))
+        channel.set_permissions.assert_not_called()
+
+    async def test_restored_overwrites(self):
+        """Channel's `send_message` and `add_reactions` overwrites were restored."""
+        await self.cog._unsilence(self.channel)
+        self.channel.set_permissions.assert_awaited_once_with(
+            self.cog._everyone_role,
+            overwrite=self.overwrite,
+        )
+
+        # Recall that these values are determined by the fixture.
+        self.assertTrue(self.overwrite.send_messages)
+        self.assertFalse(self.overwrite.add_reactions)
+
+    async def test_cache_miss_used_default_overwrites(self):
+        """Both overwrites were set to None due previous values not being found in the cache."""
+        self.cog.previous_overwrites.get.return_value = None
+
+        await self.cog._unsilence(self.channel)
+        self.channel.set_permissions.assert_awaited_once_with(
+            self.cog._everyone_role,
+            overwrite=self.overwrite,
+        )
+
+        self.assertIsNone(self.overwrite.send_messages)
+        self.assertIsNone(self.overwrite.add_reactions)
+
+    async def test_cache_miss_sent_mod_alert(self):
+        """A message was sent to the mod alerts channel."""
+        self.cog.previous_overwrites.get.return_value = None
+
+        await self.cog._unsilence(self.channel)
+        self.cog._mod_alerts_channel.send.assert_awaited_once()
+
+    async def test_removed_notifier(self):
+        """Channel was removed from `notifier`."""
+        await self.cog._unsilence(self.channel)
+        self.cog.notifier.remove_channel.assert_called_once_with(self.channel)
+
+    async def test_deleted_cached_overwrite(self):
+        """Channel was deleted from the overwrites cache."""
+        await self.cog._unsilence(self.channel)
+        self.cog.previous_overwrites.delete.assert_awaited_once_with(self.channel.id)
+
+    async def test_deleted_cached_time(self):
+        """Channel was deleted from the timestamp cache."""
+        await self.cog._unsilence(self.channel)
+        self.cog.unsilence_timestamps.delete.assert_awaited_once_with(self.channel.id)
+
+    async def test_cancelled_task(self):
+        """The scheduled unsilence task should be cancelled."""
+        await self.cog._unsilence(self.channel)
+        self.cog.scheduler.cancel.assert_called_once_with(self.channel.id)
+
+    async def test_preserved_other_overwrites(self):
+        """Channel's other unrelated overwrites were not changed, including cache misses."""
+        for overwrite_json in ('{"send_messages": true, "add_reactions": null}', None):
+            with self.subTest(overwrite_json=overwrite_json):
+                self.cog.previous_overwrites.get.return_value = overwrite_json
+
+                prev_overwrite_dict = dict(self.overwrite)
+                await self.cog._unsilence(self.channel)
+                new_overwrite_dict = dict(self.overwrite)
+
+                # Remove these keys because they were modified by the unsilence.
+                del prev_overwrite_dict['send_messages']
+                del prev_overwrite_dict['add_reactions']
+                del new_overwrite_dict['send_messages']
+                del new_overwrite_dict['add_reactions']
+
+                self.assertDictEqual(prev_overwrite_dict, new_overwrite_dict)
diff --git a/tests/bot/exts/moderation/test_slowmode.py b/tests/bot/exts/moderation/test_slowmode.py
new file mode 100644
index 000000000..dad751e0d
--- /dev/null
+++ b/tests/bot/exts/moderation/test_slowmode.py
@@ -0,0 +1,113 @@
+import unittest
+from unittest import mock
+
+from dateutil.relativedelta import relativedelta
+
+from bot.constants import Emojis
+from bot.exts.moderation.slowmode import Slowmode
+from tests.helpers import MockBot, MockContext, MockTextChannel
+
+
+class SlowmodeTests(unittest.IsolatedAsyncioTestCase):
+
+    def setUp(self) -> None:
+        self.bot = MockBot()
+        self.cog = Slowmode(self.bot)
+        self.ctx = MockContext()
+
+    async def test_get_slowmode_no_channel(self) -> None:
+        """Get slowmode without a given channel."""
+        self.ctx.channel = MockTextChannel(name='python-general', slowmode_delay=5)
+
+        await self.cog.get_slowmode(self.cog, self.ctx, None)
+        self.ctx.send.assert_called_once_with("The slowmode delay for #python-general is 5 seconds.")
+
+    async def test_get_slowmode_with_channel(self) -> None:
+        """Get slowmode with a given channel."""
+        text_channel = MockTextChannel(name='python-language', slowmode_delay=2)
+
+        await self.cog.get_slowmode(self.cog, self.ctx, text_channel)
+        self.ctx.send.assert_called_once_with('The slowmode delay for #python-language is 2 seconds.')
+
+    async def test_set_slowmode_no_channel(self) -> None:
+        """Set slowmode without a given channel."""
+        test_cases = (
+            ('helpers', 23, True, f'{Emojis.check_mark} The slowmode delay for #helpers is now 23 seconds.'),
+            ('mods', 76526, False, f'{Emojis.cross_mark} The slowmode delay must be between 0 and 6 hours.'),
+            ('admins', 97, True, f'{Emojis.check_mark} The slowmode delay for #admins is now 1 minute and 37 seconds.')
+        )
+
+        for channel_name, seconds, edited, result_msg in test_cases:
+            with self.subTest(
+                channel_mention=channel_name,
+                seconds=seconds,
+                edited=edited,
+                result_msg=result_msg
+            ):
+                self.ctx.channel = MockTextChannel(name=channel_name)
+
+                await self.cog.set_slowmode(self.cog, self.ctx, None, relativedelta(seconds=seconds))
+
+                if edited:
+                    self.ctx.channel.edit.assert_awaited_once_with(slowmode_delay=float(seconds))
+                else:
+                    self.ctx.channel.edit.assert_not_called()
+
+                self.ctx.send.assert_called_once_with(result_msg)
+
+            self.ctx.reset_mock()
+
+    async def test_set_slowmode_with_channel(self) -> None:
+        """Set slowmode with a given channel."""
+        test_cases = (
+            ('bot-commands', 12, True, f'{Emojis.check_mark} The slowmode delay for #bot-commands is now 12 seconds.'),
+            ('mod-spam', 21, True, f'{Emojis.check_mark} The slowmode delay for #mod-spam is now 21 seconds.'),
+            ('admin-spam', 4323598, False, f'{Emojis.cross_mark} The slowmode delay must be between 0 and 6 hours.')
+        )
+
+        for channel_name, seconds, edited, result_msg in test_cases:
+            with self.subTest(
+                channel_mention=channel_name,
+                seconds=seconds,
+                edited=edited,
+                result_msg=result_msg
+            ):
+                text_channel = MockTextChannel(name=channel_name)
+
+                await self.cog.set_slowmode(self.cog, self.ctx, text_channel, relativedelta(seconds=seconds))
+
+                if edited:
+                    text_channel.edit.assert_awaited_once_with(slowmode_delay=float(seconds))
+                else:
+                    text_channel.edit.assert_not_called()
+
+                self.ctx.send.assert_called_once_with(result_msg)
+
+            self.ctx.reset_mock()
+
+    async def test_reset_slowmode_no_channel(self) -> None:
+        """Reset slowmode without a given channel."""
+        self.ctx.channel = MockTextChannel(name='careers', slowmode_delay=6)
+
+        await self.cog.reset_slowmode(self.cog, self.ctx, None)
+        self.ctx.send.assert_called_once_with(
+            f'{Emojis.check_mark} The slowmode delay for #careers has been reset to 0 seconds.'
+        )
+
+    async def test_reset_slowmode_with_channel(self) -> None:
+        """Reset slowmode with a given channel."""
+        text_channel = MockTextChannel(name='meta', slowmode_delay=1)
+
+        await self.cog.reset_slowmode(self.cog, self.ctx, text_channel)
+        self.ctx.send.assert_called_once_with(
+            f'{Emojis.check_mark} The slowmode delay for #meta has been reset to 0 seconds.'
+        )
+
+    @mock.patch("bot.exts.moderation.slowmode.has_any_role")
+    @mock.patch("bot.exts.moderation.slowmode.MODERATION_ROLES", new=(1, 2, 3))
+    async def test_cog_check(self, role_check):
+        """Role check is called with `MODERATION_ROLES`"""
+        role_check.return_value.predicate = mock.AsyncMock()
+        await self.cog.cog_check(self.ctx)
+        role_check.assert_called_once_with(*(1, 2, 3))
+        role_check.return_value.predicate.assert_awaited_once_with(self.ctx)
diff --git a/tests/bot/exts/test_cogs.py b/tests/bot/exts/test_cogs.py
new file mode 100644
index 000000000..f8e120262
--- /dev/null
+++ b/tests/bot/exts/test_cogs.py
@@ -0,0 +1,82 @@
+"""Test suite for general tests which apply to all cogs."""
+
+import importlib
+import pkgutil
+import typing as t
+import unittest
+from collections import defaultdict
+from types import ModuleType
+from unittest import mock
+
+from discord.ext import commands
+
+from bot import exts
+
+
+class CommandNameTests(unittest.TestCase):
+    """Tests for shadowing command names and aliases."""
+
+    @staticmethod
+    def walk_commands(cog: commands.Cog) -> t.Iterator[commands.Command]:
+        """An iterator that recursively walks through `cog`'s commands and subcommands."""
+        # Can't use Bot.walk_commands() or Cog.get_commands() cause those are instance methods.
+        for command in cog.__cog_commands__:
+            if command.parent is None:
+                yield command
+                if isinstance(command, commands.GroupMixin):
+                    # Annoyingly it returns duplicates for each alias so use a set to fix that
+                    yield from set(command.walk_commands())
+
+    @staticmethod
+    def walk_modules() -> t.Iterator[ModuleType]:
+        """Yield imported modules from the bot.exts subpackage."""
+        def on_error(name: str) -> t.NoReturn:
+            raise ImportError(name=name)  # pragma: no cover
+
+        # The mock prevents asyncio.get_event_loop() from being called.
+        with mock.patch("discord.ext.tasks.loop"):
+            prefix = f"{exts.__name__}."
+            for module in pkgutil.walk_packages(exts.__path__, prefix, onerror=on_error):
+                if not module.ispkg:
+                    yield importlib.import_module(module.name)
+
+    @staticmethod
+    def walk_cogs(module: ModuleType) -> t.Iterator[commands.Cog]:
+        """Yield all cogs defined in an extension."""
+        for obj in module.__dict__.values():
+            # Check if it's a class type cause otherwise issubclass() may raise a TypeError.
+            is_cog = isinstance(obj, type) and issubclass(obj, commands.Cog)
+            if is_cog and obj.__module__ == module.__name__:
+                yield obj
+
+    @staticmethod
+    def get_qualified_names(command: commands.Command) -> t.List[str]:
+        """Return a list of all qualified names, including aliases, for the `command`."""
+        names = [f"{command.full_parent_name} {alias}".strip() for alias in command.aliases]
+        names.append(command.qualified_name)
+        names += getattr(command, "root_aliases", [])
+
+        return names
+
+    def get_all_commands(self) -> t.Iterator[commands.Command]:
+        """Yield all commands for all cogs in all extensions."""
+        for module in self.walk_modules():
+            for cog in self.walk_cogs(module):
+                for cmd in self.walk_commands(cog):
+                    yield cmd
+
+    def test_names_dont_shadow(self):
+        """Names and aliases of commands should be unique."""
+        all_names = defaultdict(list)
+        for cmd in self.get_all_commands():
+            func_name = f"{cmd.module}.{cmd.callback.__qualname__}"
+
+            for name in self.get_qualified_names(cmd):
+                with self.subTest(cmd=func_name, name=name):
+                    if name in all_names:  # pragma: no cover
+                        conflicts = ", ".join(all_names.get(name, ""))
+                        self.fail(
+                            f"Name '{name}' of the command {func_name} conflicts with {conflicts}."
+                        )
+
+                all_names[name].append(func_name)
diff --git a/tests/bot/exts/utils/__init__.py b/tests/bot/exts/utils/__init__.py
new file mode 100644
index 000000000..e69de29bb
--- /dev/null
+++ b/tests/bot/exts/utils/__init__.py
diff --git a/tests/bot/exts/utils/test_jams.py b/tests/bot/exts/utils/test_jams.py
new file mode 100644
index 000000000..45e7b5b51
--- /dev/null
+++ b/tests/bot/exts/utils/test_jams.py
@@ -0,0 +1,173 @@
+import unittest
+from unittest.mock import AsyncMock, MagicMock, create_autospec
+
+from discord import CategoryChannel
+
+from bot.constants import Roles
+from bot.exts.utils import jams
+from tests.helpers import MockBot, MockContext, MockGuild, MockMember, MockRole, MockTextChannel
+
+
+def get_mock_category(channel_count: int, name: str) -> CategoryChannel:
+    """Return a mocked code jam category."""
+    category = create_autospec(CategoryChannel, spec_set=True, instance=True)
+    category.name = name
+    category.channels = [MockTextChannel() for _ in range(channel_count)]
+
+    return category
+
+
+class JamCreateTeamTests(unittest.IsolatedAsyncioTestCase):
+    """Tests for `createteam` command."""
+
+    def setUp(self):
+        self.bot = MockBot()
+        self.admin_role = MockRole(name="Admins", id=Roles.admins)
+        self.command_user = MockMember([self.admin_role])
+        self.guild = MockGuild([self.admin_role])
+        self.ctx = MockContext(bot=self.bot, author=self.command_user, guild=self.guild)
+        self.cog = jams.CodeJams(self.bot)
+
+    async def test_too_small_amount_of_team_members_passed(self):
+        """Should `ctx.send` and exit early when too small amount of members."""
+        for case in (1, 2):
+            with self.subTest(amount_of_members=case):
+                self.cog.create_channels = AsyncMock()
+                self.cog.add_roles = AsyncMock()
+
+                self.ctx.reset_mock()
+                members = (MockMember() for _ in range(case))
+                await self.cog.createteam(self.cog, self.ctx, "foo", members)
+
+                self.ctx.send.assert_awaited_once()
+                self.cog.create_channels.assert_not_awaited()
+                self.cog.add_roles.assert_not_awaited()
+
+    async def test_duplicate_members_provided(self):
+        """Should `ctx.send` and exit early because duplicate members provided and total there is only 1 member."""
+        self.cog.create_channels = AsyncMock()
+        self.cog.add_roles = AsyncMock()
+
+        member = MockMember()
+        await self.cog.createteam(self.cog, self.ctx, "foo", (member for _ in range(5)))
+
+        self.ctx.send.assert_awaited_once()
+        self.cog.create_channels.assert_not_awaited()
+        self.cog.add_roles.assert_not_awaited()
+
+    async def test_result_sending(self):
+        """Should call `ctx.send` when everything goes right."""
+        self.cog.create_channels = AsyncMock()
+        self.cog.add_roles = AsyncMock()
+
+        members = [MockMember() for _ in range(5)]
+        await self.cog.createteam(self.cog, self.ctx, "foo", members)
+
+        self.cog.create_channels.assert_awaited_once()
+        self.cog.add_roles.assert_awaited_once()
+        self.ctx.send.assert_awaited_once()
+
+    async def test_category_doesnt_exist(self):
+        """Should create a new code jam category."""
+        subtests = (
+            [],
+            [get_mock_category(jams.MAX_CHANNELS - 1, jams.CATEGORY_NAME)],
+            [get_mock_category(jams.MAX_CHANNELS - 2, "other")],
+        )
+
+        for categories in subtests:
+            self.guild.reset_mock()
+            self.guild.categories = categories
+
+            with self.subTest(categories=categories):
+                actual_category = await self.cog.get_category(self.guild)
+
+                self.guild.create_category_channel.assert_awaited_once()
+                category_overwrites = self.guild.create_category_channel.call_args[1]["overwrites"]
+
+                self.assertFalse(category_overwrites[self.guild.default_role].read_messages)
+                self.assertTrue(category_overwrites[self.guild.me].read_messages)
+                self.assertEqual(self.guild.create_category_channel.return_value, actual_category)
+
+    async def test_category_channel_exist(self):
+        """Should not try to create category channel."""
+        expected_category = get_mock_category(jams.MAX_CHANNELS - 2, jams.CATEGORY_NAME)
+        self.guild.categories = [
+            get_mock_category(jams.MAX_CHANNELS - 2, "other"),
+            expected_category,
+            get_mock_category(0, jams.CATEGORY_NAME),
+        ]
+
+        actual_category = await self.cog.get_category(self.guild)
+        self.assertEqual(expected_category, actual_category)
+
+    async def test_channel_overwrites(self):
+        """Should have correct permission overwrites for users and roles."""
+        leader = MockMember()
+        members = [leader] + [MockMember() for _ in range(4)]
+        overwrites = self.cog.get_overwrites(members, self.guild)
+
+        # Leader permission overwrites
+        self.assertTrue(overwrites[leader].manage_messages)
+        self.assertTrue(overwrites[leader].read_messages)
+        self.assertTrue(overwrites[leader].manage_webhooks)
+        self.assertTrue(overwrites[leader].connect)
+
+        # Other members permission overwrites
+        for member in members[1:]:
+            self.assertTrue(overwrites[member].read_messages)
+            self.assertTrue(overwrites[member].connect)
+
+        # Everyone and verified role overwrite
+        self.assertFalse(overwrites[self.guild.default_role].read_messages)
+        self.assertFalse(overwrites[self.guild.default_role].connect)
+        self.assertFalse(overwrites[self.guild.get_role(Roles.verified)].read_messages)
+        self.assertFalse(overwrites[self.guild.get_role(Roles.verified)].connect)
+
+    async def test_team_channels_creation(self):
+        """Should create new voice and text channel for team."""
+        members = [MockMember() for _ in range(5)]
+
+        self.cog.get_overwrites = MagicMock()
+        self.cog.get_category = AsyncMock()
+        self.ctx.guild.create_text_channel.return_value = MockTextChannel(mention="foobar-channel")
+        actual = await self.cog.create_channels(self.guild, "my-team", members)
+
+        self.assertEqual("foobar-channel", actual)
+        self.cog.get_overwrites.assert_called_once_with(members, self.guild)
+        self.cog.get_category.assert_awaited_once_with(self.guild)
+
+        self.guild.create_text_channel.assert_awaited_once_with(
+            "my-team",
+            overwrites=self.cog.get_overwrites.return_value,
+            category=self.cog.get_category.return_value
+        )
+        self.guild.create_voice_channel.assert_awaited_once_with(
+            "My Team",
+            overwrites=self.cog.get_overwrites.return_value,
+            category=self.cog.get_category.return_value
+        )
+
+    async def test_jam_roles_adding(self):
+        """Should add team leader role to leader and jam role to every team member."""
+        leader_role = MockRole(name="Team Leader")
+        jam_role = MockRole(name="Jammer")
+        self.guild.get_role.side_effect = [leader_role, jam_role]
+
+        leader = MockMember()
+        members = [leader] + [MockMember() for _ in range(4)]
+        await self.cog.add_roles(self.guild, members)
+
+        leader.add_roles.assert_any_await(leader_role)
+        for member in members:
+            member.add_roles.assert_any_await(jam_role)
+
+
+class CodeJamSetup(unittest.TestCase):
+    """Test for `setup` function of `CodeJam` cog."""
+
+    def test_setup(self):
+        """Should call `bot.add_cog`."""
+        bot = MockBot()
+        jams.setup(bot)
+        bot.add_cog.assert_called_once()
diff --git a/tests/bot/exts/utils/test_snekbox.py b/tests/bot/exts/utils/test_snekbox.py
new file mode 100644
index 000000000..321a92445
--- /dev/null
+++ b/tests/bot/exts/utils/test_snekbox.py
@@ -0,0 +1,384 @@
+import asyncio
+import unittest
+from unittest.mock import AsyncMock, MagicMock, Mock, call, create_autospec, patch
+
+from discord.ext import commands
+
+from bot import constants
+from bot.exts.utils import snekbox
+from bot.exts.utils.snekbox import Snekbox
+from tests.helpers import MockBot, MockContext, MockMessage, MockReaction, MockUser
+
+
+class SnekboxTests(unittest.IsolatedAsyncioTestCase):
+    def setUp(self):
+        """Add mocked bot and cog to the instance."""
+        self.bot = MockBot()
+        self.cog = Snekbox(bot=self.bot)
+
+    async def test_post_eval(self):
+        """Post the eval code to the URLs.snekbox_eval_api endpoint."""
+        resp = MagicMock()
+        resp.json = AsyncMock(return_value="return")
+
+        context_manager = MagicMock()
+        context_manager.__aenter__.return_value = resp
+        self.bot.http_session.post.return_value = context_manager
+
+        self.assertEqual(await self.cog.post_eval("import random"), "return")
+        self.bot.http_session.post.assert_called_with(
+            constants.URLs.snekbox_eval_api,
+            json={"input": "import random"},
+            raise_for_status=True
+        )
+        resp.json.assert_awaited_once()
+
+    async def test_upload_output_reject_too_long(self):
+        """Reject output longer than MAX_PASTE_LEN."""
+        result = await self.cog.upload_output("-" * (snekbox.MAX_PASTE_LEN + 1))
+        self.assertEqual(result, "too long to upload")
+
+    @patch("bot.exts.utils.snekbox.send_to_paste_service")
+    async def test_upload_output(self, mock_paste_util):
+        """Upload the eval output to the URLs.paste_service.format(key="documents") endpoint."""
+        await self.cog.upload_output("Test output.")
+        mock_paste_util.assert_called_once_with("Test output.", extension="txt")
+
+    def test_prepare_input(self):
+        cases = (
+            ('print("Hello world!")', 'print("Hello world!")', 'non-formatted'),
+            ('`print("Hello world!")`', 'print("Hello world!")', 'one line code block'),
+            ('```\nprint("Hello world!")```', 'print("Hello world!")', 'multiline code block'),
+            ('```py\nprint("Hello world!")```', 'print("Hello world!")', 'multiline python code block'),
+            ('text```print("Hello world!")```text', 'print("Hello world!")', 'code block surrounded by text'),
+            ('```print("Hello world!")```\ntext\n```py\nprint("Hello world!")```',
+             'print("Hello world!")\nprint("Hello world!")', 'two code blocks with text in-between'),
+            ('`print("Hello world!")`\ntext\n```print("How\'s it going?")```',
+             'print("How\'s it going?")', 'code block preceded by inline code'),
+            ('`print("Hello world!")`\ntext\n`print("Hello world!")`',
+             'print("Hello world!")', 'one inline code block of two')
+        )
+        for case, expected, testname in cases:
+            with self.subTest(msg=f'Extract code from {testname}.'):
+                self.assertEqual(self.cog.prepare_input(case), expected)
+
+    def test_get_results_message(self):
+        """Return error and message according to the eval result."""
+        cases = (
+            ('ERROR', None, ('Your eval job has failed', 'ERROR')),
+            ('', 128 + snekbox.SIGKILL, ('Your eval job timed out or ran out of memory', '')),
+            ('', 255, ('Your eval job has failed', 'A fatal NsJail error occurred'))
+        )
+        for stdout, returncode, expected in cases:
+            with self.subTest(stdout=stdout, returncode=returncode, expected=expected):
+                actual = self.cog.get_results_message({'stdout': stdout, 'returncode': returncode})
+                self.assertEqual(actual, expected)
+
+    @patch('bot.exts.utils.snekbox.Signals', side_effect=ValueError)
+    def test_get_results_message_invalid_signal(self, mock_signals: Mock):
+        self.assertEqual(
+            self.cog.get_results_message({'stdout': '', 'returncode': 127}),
+            ('Your eval job has completed with return code 127', '')
+        )
+
+    @patch('bot.exts.utils.snekbox.Signals')
+    def test_get_results_message_valid_signal(self, mock_signals: Mock):
+        mock_signals.return_value.name = 'SIGTEST'
+        self.assertEqual(
+            self.cog.get_results_message({'stdout': '', 'returncode': 127}),
+            ('Your eval job has completed with return code 127 (SIGTEST)', '')
+        )
+
+    def test_get_status_emoji(self):
+        """Return emoji according to the eval result."""
+        cases = (
+            (' ', -1, ':warning:'),
+            ('Hello world!', 0, ':white_check_mark:'),
+            ('Invalid beard size', -1, ':x:')
+        )
+        for stdout, returncode, expected in cases:
+            with self.subTest(stdout=stdout, returncode=returncode, expected=expected):
+                actual = self.cog.get_status_emoji({'stdout': stdout, 'returncode': returncode})
+                self.assertEqual(actual, expected)
+
+    async def test_format_output(self):
+        """Test output formatting."""
+        self.cog.upload_output = AsyncMock(return_value='https://testificate.com/')
+
+        too_many_lines = (
+            '001 | v\n002 | e\n003 | r\n004 | y\n005 | l\n006 | o\n'
+            '007 | n\n008 | g\n009 | b\n010 | e\n011 | a\n... (truncated - too many lines)'
+        )
+        too_long_too_many_lines = (
+            "\n".join(
+                f"{i:03d} | {line}" for i, line in enumerate(['verylongbeard' * 10] * 15, 1)
+            )[:1000] + "\n... (truncated - too long, too many lines)"
+        )
+
+        cases = (
+            ('', ('[No output]', None), 'No output'),
+            ('My awesome output', ('My awesome output', None), 'One line output'),
+            ('<@', ("<@\u200B", None), r'Convert <@ to <@\u200B'),
+            ('<!@', ("<!@\u200B", None), r'Convert <!@ to <!@\u200B'),
+            (
+                '\u202E\u202E\u202E',
+                ('Code block escape attempt detected; will not output result', 'https://testificate.com/'),
+                'Detect RIGHT-TO-LEFT OVERRIDE'
+            ),
+            (
+                '\u200B\u200B\u200B',
+                ('Code block escape attempt detected; will not output result', 'https://testificate.com/'),
+                'Detect ZERO WIDTH SPACE'
+            ),
+            ('long\nbeard', ('001 | long\n002 | beard', None), 'Two line output'),
+            (
+                'v\ne\nr\ny\nl\no\nn\ng\nb\ne\na\nr\nd',
+                (too_many_lines, 'https://testificate.com/'),
+                '12 lines output'
+            ),
+            (
+                'verylongbeard' * 100,
+                ('verylongbeard' * 76 + 'verylongbear\n... (truncated - too long)', 'https://testificate.com/'),
+                '1300 characters output'
+            ),
+            (
+                ('verylongbeard' * 10 + '\n') * 15,
+                (too_long_too_many_lines, 'https://testificate.com/'),
+                '15 lines, 1965 characters output'
+            ),
+        )
+        for case, expected, testname in cases:
+            with self.subTest(msg=testname, case=case, expected=expected):
+                self.assertEqual(await self.cog.format_output(case), expected)
+
+    async def test_eval_command_evaluate_once(self):
+        """Test the eval command procedure."""
+        ctx = MockContext()
+        response = MockMessage()
+        self.cog.prepare_input = MagicMock(return_value='MyAwesomeFormattedCode')
+        self.cog.send_eval = AsyncMock(return_value=response)
+        self.cog.continue_eval = AsyncMock(return_value=None)
+
+        await self.cog.eval_command(self.cog, ctx=ctx, code='MyAwesomeCode')
+        self.cog.prepare_input.assert_called_once_with('MyAwesomeCode')
+        self.cog.send_eval.assert_called_once_with(ctx, 'MyAwesomeFormattedCode')
+        self.cog.continue_eval.assert_called_once_with(ctx, response)
+
+    async def test_eval_command_evaluate_twice(self):
+        """Test the eval and re-eval command procedure."""
+        ctx = MockContext()
+        response = MockMessage()
+        self.cog.prepare_input = MagicMock(return_value='MyAwesomeFormattedCode')
+        self.cog.send_eval = AsyncMock(return_value=response)
+        self.cog.continue_eval = AsyncMock()
+        self.cog.continue_eval.side_effect = ('MyAwesomeCode-2', None)
+
+        await self.cog.eval_command(self.cog, ctx=ctx, code='MyAwesomeCode')
+        self.cog.prepare_input.has_calls(call('MyAwesomeCode'), call('MyAwesomeCode-2'))
+        self.cog.send_eval.assert_called_with(ctx, 'MyAwesomeFormattedCode')
+        self.cog.continue_eval.assert_called_with(ctx, response)
+
+    async def test_eval_command_reject_two_eval_at_the_same_time(self):
+        """Test if the eval command rejects an eval if the author already have a running eval."""
+        ctx = MockContext()
+        ctx.author.id = 42
+        ctx.author.mention = '@LemonLemonishBeard#0042'
+        ctx.send = AsyncMock()
+        self.cog.jobs = (42,)
+        await self.cog.eval_command(self.cog, ctx=ctx, code='MyAwesomeCode')
+        ctx.send.assert_called_once_with(
+            "@LemonLemonishBeard#0042 You've already got a job running - please wait for it to finish!"
+        )
+
+    async def test_eval_command_call_help(self):
+        """Test if the eval command call the help command if no code is provided."""
+        ctx = MockContext(command="sentinel")
+        await self.cog.eval_command(self.cog, ctx=ctx, code='')
+        ctx.send_help.assert_called_once_with(ctx.command)
+
+    async def test_send_eval(self):
+        """Test the send_eval function."""
+        ctx = MockContext()
+        ctx.message = MockMessage()
+        ctx.send = AsyncMock()
+        ctx.author.mention = '@LemonLemonishBeard#0042'
+
+        self.cog.post_eval = AsyncMock(return_value={'stdout': '', 'returncode': 0})
+        self.cog.get_results_message = MagicMock(return_value=('Return code 0', ''))
+        self.cog.get_status_emoji = MagicMock(return_value=':yay!:')
+        self.cog.format_output = AsyncMock(return_value=('[No output]', None))
+
+        mocked_filter_cog = MagicMock()
+        mocked_filter_cog.filter_eval = AsyncMock(return_value=False)
+        self.bot.get_cog.return_value = mocked_filter_cog
+
+        await self.cog.send_eval(ctx, 'MyAwesomeCode')
+        ctx.send.assert_called_once_with(
+            '@LemonLemonishBeard#0042 :yay!: Return code 0.\n\n```\n[No output]\n```'
+        )
+        self.cog.post_eval.assert_called_once_with('MyAwesomeCode')
+        self.cog.get_status_emoji.assert_called_once_with({'stdout': '', 'returncode': 0})
+        self.cog.get_results_message.assert_called_once_with({'stdout': '', 'returncode': 0})
+        self.cog.format_output.assert_called_once_with('')
+
+    async def test_send_eval_with_paste_link(self):
+        """Test the send_eval function with a too long output that generate a paste link."""
+        ctx = MockContext()
+        ctx.message = MockMessage()
+        ctx.send = AsyncMock()
+        ctx.author.mention = '@LemonLemonishBeard#0042'
+
+        self.cog.post_eval = AsyncMock(return_value={'stdout': 'Way too long beard', 'returncode': 0})
+        self.cog.get_results_message = MagicMock(return_value=('Return code 0', ''))
+        self.cog.get_status_emoji = MagicMock(return_value=':yay!:')
+        self.cog.format_output = AsyncMock(return_value=('Way too long beard', 'lookatmybeard.com'))
+
+        mocked_filter_cog = MagicMock()
+        mocked_filter_cog.filter_eval = AsyncMock(return_value=False)
+        self.bot.get_cog.return_value = mocked_filter_cog
+
+        await self.cog.send_eval(ctx, 'MyAwesomeCode')
+        ctx.send.assert_called_once_with(
+            '@LemonLemonishBeard#0042 :yay!: Return code 0.'
+            '\n\n```\nWay too long beard\n```\nFull output: lookatmybeard.com'
+        )
+        self.cog.post_eval.assert_called_once_with('MyAwesomeCode')
+        self.cog.get_status_emoji.assert_called_once_with({'stdout': 'Way too long beard', 'returncode': 0})
+        self.cog.get_results_message.assert_called_once_with({'stdout': 'Way too long beard', 'returncode': 0})
+        self.cog.format_output.assert_called_once_with('Way too long beard')
+
+    async def test_send_eval_with_non_zero_eval(self):
+        """Test the send_eval function with a code returning a non-zero code."""
+        ctx = MockContext()
+        ctx.message = MockMessage()
+        ctx.send = AsyncMock()
+        ctx.author.mention = '@LemonLemonishBeard#0042'
+        self.cog.post_eval = AsyncMock(return_value={'stdout': 'ERROR', 'returncode': 127})
+        self.cog.get_results_message = MagicMock(return_value=('Return code 127', 'Beard got stuck in the eval'))
+        self.cog.get_status_emoji = MagicMock(return_value=':nope!:')
+        self.cog.format_output = AsyncMock()  # This function isn't called
+
+        mocked_filter_cog = MagicMock()
+        mocked_filter_cog.filter_eval = AsyncMock(return_value=False)
+        self.bot.get_cog.return_value = mocked_filter_cog
+
+        await self.cog.send_eval(ctx, 'MyAwesomeCode')
+        ctx.send.assert_called_once_with(
+            '@LemonLemonishBeard#0042 :nope!: Return code 127.\n\n```\nBeard got stuck in the eval\n```'
+        )
+        self.cog.post_eval.assert_called_once_with('MyAwesomeCode')
+        self.cog.get_status_emoji.assert_called_once_with({'stdout': 'ERROR', 'returncode': 127})
+        self.cog.get_results_message.assert_called_once_with({'stdout': 'ERROR', 'returncode': 127})
+        self.cog.format_output.assert_not_called()
+
+    @patch("bot.exts.utils.snekbox.partial")
+    async def test_continue_eval_does_continue(self, partial_mock):
+        """Test that the continue_eval function does continue if required conditions are met."""
+        ctx = MockContext(message=MockMessage(add_reaction=AsyncMock(), clear_reactions=AsyncMock()))
+        response = MockMessage(delete=AsyncMock())
+        new_msg = MockMessage()
+        self.bot.wait_for.side_effect = ((None, new_msg), None)
+        expected = "NewCode"
+        self.cog.get_code = create_autospec(self.cog.get_code, spec_set=True, return_value=expected)
+
+        actual = await self.cog.continue_eval(ctx, response)
+        self.cog.get_code.assert_awaited_once_with(new_msg)
+        self.assertEqual(actual, expected)
+        self.bot.wait_for.assert_has_awaits(
+            (
+                call(
+                    'message_edit',
+                    check=partial_mock(snekbox.predicate_eval_message_edit, ctx),
+                    timeout=snekbox.REEVAL_TIMEOUT,
+                ),
+                call('reaction_add', check=partial_mock(snekbox.predicate_eval_emoji_reaction, ctx), timeout=10)
+            )
+        )
+        ctx.message.add_reaction.assert_called_once_with(snekbox.REEVAL_EMOJI)
+        ctx.message.clear_reaction.assert_called_once_with(snekbox.REEVAL_EMOJI)
+        response.delete.assert_called_once()
+
+    async def test_continue_eval_does_not_continue(self):
+        ctx = MockContext(message=MockMessage(clear_reactions=AsyncMock()))
+        self.bot.wait_for.side_effect = asyncio.TimeoutError
+
+        actual = await self.cog.continue_eval(ctx, MockMessage())
+        self.assertEqual(actual, None)
+        ctx.message.clear_reaction.assert_called_once_with(snekbox.REEVAL_EMOJI)
+
+    async def test_get_code(self):
+        """Should return 1st arg (or None) if eval cmd in message, otherwise return full content."""
+        prefix = constants.Bot.prefix
+        subtests = (
+            (self.cog.eval_command, f"{prefix}{self.cog.eval_command.name} print(1)", "print(1)"),
+            (self.cog.eval_command, f"{prefix}{self.cog.eval_command.name}", None),
+            (MagicMock(spec=commands.Command), f"{prefix}tags get foo"),
+            (None, "print(123)")
+        )
+
+        for command, content, *expected_code in subtests:
+            if not expected_code:
+                expected_code = content
+            else:
+                [expected_code] = expected_code
+
+            with self.subTest(content=content, expected_code=expected_code):
+                self.bot.get_context.reset_mock()
+                self.bot.get_context.return_value = MockContext(command=command)
+                message = MockMessage(content=content)
+
+                actual_code = await self.cog.get_code(message)
+
+                self.bot.get_context.assert_awaited_once_with(message)
+                self.assertEqual(actual_code, expected_code)
+
+    def test_predicate_eval_message_edit(self):
+        """Test the predicate_eval_message_edit function."""
+        msg0 = MockMessage(id=1, content='abc')
+        msg1 = MockMessage(id=2, content='abcdef')
+        msg2 = MockMessage(id=1, content='abcdef')
+
+        cases = (
+            (msg0, msg0, False, 'same ID, same content'),
+            (msg0, msg1, False, 'different ID, different content'),
+            (msg0, msg2, True, 'same ID, different content')
+        )
+        for ctx_msg, new_msg, expected, testname in cases:
+            with self.subTest(msg=f'Messages with {testname} return {expected}'):
+                ctx = MockContext(message=ctx_msg)
+                actual = snekbox.predicate_eval_message_edit(ctx, ctx_msg, new_msg)
+                self.assertEqual(actual, expected)
+
+    def test_predicate_eval_emoji_reaction(self):
+        """Test the predicate_eval_emoji_reaction function."""
+        valid_reaction = MockReaction(message=MockMessage(id=1))
+        valid_reaction.__str__.return_value = snekbox.REEVAL_EMOJI
+        valid_ctx = MockContext(message=MockMessage(id=1), author=MockUser(id=2))
+        valid_user = MockUser(id=2)
+
+        invalid_reaction_id = MockReaction(message=MockMessage(id=42))
+        invalid_reaction_id.__str__.return_value = snekbox.REEVAL_EMOJI
+        invalid_user_id = MockUser(id=42)
+        invalid_reaction_str = MockReaction(message=MockMessage(id=1))
+        invalid_reaction_str.__str__.return_value = ':longbeard:'
+
+        cases = (
+            (invalid_reaction_id, valid_user, False, 'invalid reaction ID'),
+            (valid_reaction, invalid_user_id, False, 'invalid user ID'),
+            (invalid_reaction_str, valid_user, False, 'invalid reaction __str__'),
+            (valid_reaction, valid_user, True, 'matching attributes')
+        )
+        for reaction, user, expected, testname in cases:
+            with self.subTest(msg=f'Test with {testname} and expected return {expected}'):
+                actual = snekbox.predicate_eval_emoji_reaction(valid_ctx, reaction, user)
+                self.assertEqual(actual, expected)
+
+
+class SnekboxSetupTests(unittest.TestCase):
+    """Tests setup of the `Snekbox` cog."""
+
+    def test_setup(self):
+        """Setup of the extension should call add_cog."""
+        bot = MockBot()
+        snekbox.setup(bot)
+        bot.add_cog.assert_called_once()
diff --git a/tests/bot/rules/__init__.py b/tests/bot/rules/__init__.py
index 36c986fe1..0d570f5a3 100644
--- a/tests/bot/rules/__init__.py
+++ b/tests/bot/rules/__init__.py
@@ -12,7 +12,7 @@ class DisallowedCase(NamedTuple):
     n_violations: int
 
 
-class RuleTest(unittest.TestCase, metaclass=ABCMeta):
+class RuleTest(unittest.IsolatedAsyncioTestCase, metaclass=ABCMeta):
     """
     Abstract class for antispam rule test cases.
 
@@ -68,9 +68,9 @@ class RuleTest(unittest.TestCase, metaclass=ABCMeta):
     @abstractmethod
     def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
         """Give expected relevant messages for `case`."""
-        raise NotImplementedError
+        raise NotImplementedError  # pragma: no cover
 
     @abstractmethod
     def get_report(self, case: DisallowedCase) -> str:
         """Give expected error report for `case`."""
-        raise NotImplementedError
+        raise NotImplementedError  # pragma: no cover
diff --git a/tests/bot/rules/test_attachments.py b/tests/bot/rules/test_attachments.py
index e54b4b5b8..d7e779221 100644
--- a/tests/bot/rules/test_attachments.py
+++ b/tests/bot/rules/test_attachments.py
@@ -2,7 +2,7 @@ from typing import Iterable
 
 from bot.rules import attachments
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str, total_attachments: int) -> MockMessage:
@@ -17,7 +17,6 @@ class AttachmentRuleTests(RuleTest):
         self.apply = attachments.apply
         self.config = {"max": 5, "interval": 10}
 
-    @async_test
     async def test_allows_messages_without_too_many_attachments(self):
         """Messages without too many attachments are allowed as-is."""
         cases = (
@@ -28,7 +27,6 @@ class AttachmentRuleTests(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_disallows_messages_with_too_many_attachments(self):
         """Messages with too many attachments trigger the rule."""
         cases = (
diff --git a/tests/bot/rules/test_burst.py b/tests/bot/rules/test_burst.py
index 72f0be0c7..03682966b 100644
--- a/tests/bot/rules/test_burst.py
+++ b/tests/bot/rules/test_burst.py
@@ -2,7 +2,7 @@ from typing import Iterable
 
 from bot.rules import burst
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str) -> MockMessage:
@@ -21,7 +21,6 @@ class BurstRuleTests(RuleTest):
         self.apply = burst.apply
         self.config = {"max": 2, "interval": 10}
 
-    @async_test
     async def test_allows_messages_within_limit(self):
         """Cases which do not violate the rule."""
         cases = (
@@ -31,7 +30,6 @@ class BurstRuleTests(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_disallows_messages_beyond_limit(self):
         """Cases where the amount of messages exceeds the limit, triggering the rule."""
         cases = (
diff --git a/tests/bot/rules/test_burst_shared.py b/tests/bot/rules/test_burst_shared.py
index 47367a5f8..3275143d5 100644
--- a/tests/bot/rules/test_burst_shared.py
+++ b/tests/bot/rules/test_burst_shared.py
@@ -2,7 +2,7 @@ from typing import Iterable
 
 from bot.rules import burst_shared
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str) -> MockMessage:
@@ -21,7 +21,6 @@ class BurstSharedRuleTests(RuleTest):
         self.apply = burst_shared.apply
         self.config = {"max": 2, "interval": 10}
 
-    @async_test
     async def test_allows_messages_within_limit(self):
         """
         Cases that do not violate the rule.
@@ -34,7 +33,6 @@ class BurstSharedRuleTests(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_disallows_messages_beyond_limit(self):
         """Cases where the amount of messages exceeds the limit, triggering the rule."""
         cases = (
diff --git a/tests/bot/rules/test_chars.py b/tests/bot/rules/test_chars.py
index 7cc36f49e..f1e3c76a7 100644
--- a/tests/bot/rules/test_chars.py
+++ b/tests/bot/rules/test_chars.py
@@ -2,7 +2,7 @@ from typing import Iterable
 
 from bot.rules import chars
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str, n_chars: int) -> MockMessage:
@@ -20,7 +20,6 @@ class CharsRuleTests(RuleTest):
             "interval": 10,
         }
 
-    @async_test
     async def test_allows_messages_within_limit(self):
         """Cases with a total amount of chars within limit."""
         cases = (
@@ -31,7 +30,6 @@ class CharsRuleTests(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_disallows_messages_beyond_limit(self):
         """Cases where the total amount of chars exceeds the limit, triggering the rule."""
         cases = (
diff --git a/tests/bot/rules/test_discord_emojis.py b/tests/bot/rules/test_discord_emojis.py
index 0239b0b00..66c2d9f92 100644
--- a/tests/bot/rules/test_discord_emojis.py
+++ b/tests/bot/rules/test_discord_emojis.py
@@ -2,14 +2,15 @@ from typing import Iterable
 
 from bot.rules import discord_emojis
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 discord_emoji = "<:abcd:1234>"  # Discord emojis follow the format <:name:id>
+unicode_emoji = "🧪"
 
 
-def make_msg(author: str, n_emojis: int) -> MockMessage:
+def make_msg(author: str, n_emojis: int, emoji: str = discord_emoji) -> MockMessage:
     """Build a MockMessage instance with content containing `n_emojis` arbitrary emojis."""
-    return MockMessage(author=author, content=discord_emoji * n_emojis)
+    return MockMessage(author=author, content=emoji * n_emojis)
 
 
 class DiscordEmojisRuleTests(RuleTest):
@@ -19,19 +20,23 @@ class DiscordEmojisRuleTests(RuleTest):
         self.apply = discord_emojis.apply
         self.config = {"max": 2, "interval": 10}
 
-    @async_test
     async def test_allows_messages_within_limit(self):
-        """Cases with a total amount of discord emojis within limit."""
+        """Cases with a total amount of discord and unicode emojis within limit."""
         cases = (
             [make_msg("bob", 2)],
             [make_msg("alice", 1), make_msg("bob", 2), make_msg("alice", 1)],
+            [make_msg("bob", 2, unicode_emoji)],
+            [
+                make_msg("alice", 1, unicode_emoji),
+                make_msg("bob", 2, unicode_emoji),
+                make_msg("alice", 1, unicode_emoji)
+            ],
         )
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_disallows_messages_beyond_limit(self):
-        """Cases with more than the allowed amount of discord emojis."""
+        """Cases with more than the allowed amount of discord and unicode emojis."""
         cases = (
             DisallowedCase(
                 [make_msg("bob", 3)],
@@ -43,6 +48,20 @@ class DiscordEmojisRuleTests(RuleTest):
                 ("alice",),
                 4,
             ),
+            DisallowedCase(
+                [make_msg("bob", 3, unicode_emoji)],
+                ("bob",),
+                3,
+            ),
+            DisallowedCase(
+                [
+                    make_msg("alice", 2, unicode_emoji),
+                    make_msg("bob", 2, unicode_emoji),
+                    make_msg("alice", 2, unicode_emoji)
+                ],
+                ("alice",),
+                4
+            )
         )
 
         await self.run_disallowed(cases)
diff --git a/tests/bot/rules/test_duplicates.py b/tests/bot/rules/test_duplicates.py
index 59e0fb6ef..9bd886a77 100644
--- a/tests/bot/rules/test_duplicates.py
+++ b/tests/bot/rules/test_duplicates.py
@@ -2,7 +2,7 @@ from typing import Iterable
 
 from bot.rules import duplicates
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str, content: str) -> MockMessage:
@@ -17,7 +17,6 @@ class DuplicatesRuleTests(RuleTest):
         self.apply = duplicates.apply
         self.config = {"max": 2, "interval": 10}
 
-    @async_test
     async def test_allows_messages_within_limit(self):
         """Cases which do not violate the rule."""
         cases = (
@@ -28,7 +27,6 @@ class DuplicatesRuleTests(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_disallows_messages_beyond_limit(self):
         """Cases with too many duplicate messages from the same author."""
         cases = (
diff --git a/tests/bot/rules/test_links.py b/tests/bot/rules/test_links.py
index 3c3f90e5f..b091bd9d7 100644
--- a/tests/bot/rules/test_links.py
+++ b/tests/bot/rules/test_links.py
@@ -2,7 +2,7 @@ from typing import Iterable
 
 from bot.rules import links
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str, total_links: int) -> MockMessage:
@@ -21,7 +21,6 @@ class LinksTests(RuleTest):
             "interval": 10
         }
 
-    @async_test
     async def test_links_within_limit(self):
         """Messages with an allowed amount of links."""
         cases = (
@@ -34,7 +33,6 @@ class LinksTests(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_links_exceeding_limit(self):
         """Messages with a a higher than allowed amount of links."""
         cases = (
diff --git a/tests/bot/rules/test_mentions.py b/tests/bot/rules/test_mentions.py
index ebcdabac6..6444532f2 100644
--- a/tests/bot/rules/test_mentions.py
+++ b/tests/bot/rules/test_mentions.py
@@ -2,7 +2,7 @@ from typing import Iterable
 
 from bot.rules import mentions
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str, total_mentions: int) -> MockMessage:
@@ -20,7 +20,6 @@ class TestMentions(RuleTest):
             "interval": 10,
         }
 
-    @async_test
     async def test_mentions_within_limit(self):
         """Messages with an allowed amount of mentions."""
         cases = (
@@ -32,7 +31,6 @@ class TestMentions(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_mentions_exceeding_limit(self):
         """Messages with a higher than allowed amount of mentions."""
         cases = (
diff --git a/tests/bot/rules/test_newlines.py b/tests/bot/rules/test_newlines.py
index d61c4609d..e35377773 100644
--- a/tests/bot/rules/test_newlines.py
+++ b/tests/bot/rules/test_newlines.py
@@ -2,7 +2,7 @@ from typing import Iterable, List
 
 from bot.rules import newlines
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str, newline_groups: List[int]) -> MockMessage:
@@ -29,7 +29,6 @@ class TotalNewlinesRuleTests(RuleTest):
             "interval": 10,
         }
 
-    @async_test
     async def test_allows_messages_within_limit(self):
         """Cases which do not violate the rule."""
         cases = (
@@ -41,7 +40,6 @@ class TotalNewlinesRuleTests(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_disallows_messages_total(self):
         """Cases which violate the rule by having too many newlines in total."""
         cases = (
@@ -79,7 +77,6 @@ class GroupNewlinesRuleTests(RuleTest):
         self.apply = newlines.apply
         self.config = {"max": 5, "max_consecutive": 3, "interval": 10}
 
-    @async_test
     async def test_disallows_messages_consecutive(self):
         """Cases which violate the rule due to having too many consecutive newlines."""
         cases = (
diff --git a/tests/bot/rules/test_role_mentions.py b/tests/bot/rules/test_role_mentions.py
index b339cccf7..26c05d527 100644
--- a/tests/bot/rules/test_role_mentions.py
+++ b/tests/bot/rules/test_role_mentions.py
@@ -2,7 +2,7 @@ from typing import Iterable
 
 from bot.rules import role_mentions
 from tests.bot.rules import DisallowedCase, RuleTest
-from tests.helpers import MockMessage, async_test
+from tests.helpers import MockMessage
 
 
 def make_msg(author: str, n_mentions: int) -> MockMessage:
@@ -17,7 +17,6 @@ class RoleMentionsRuleTests(RuleTest):
         self.apply = role_mentions.apply
         self.config = {"max": 2, "interval": 10}
 
-    @async_test
     async def test_allows_messages_within_limit(self):
         """Cases with a total amount of role mentions within limit."""
         cases = (
@@ -27,7 +26,6 @@ class RoleMentionsRuleTests(RuleTest):
 
         await self.run_allowed(cases)
 
-    @async_test
     async def test_disallows_messages_beyond_limit(self):
         """Cases with more than the allowed amount of role mentions."""
         cases = (
diff --git a/tests/bot/test_api.py b/tests/bot/test_api.py
index bdfcc73e4..76bcb481d 100644
--- a/tests/bot/test_api.py
+++ b/tests/bot/test_api.py
@@ -2,10 +2,9 @@ import unittest
 from unittest.mock import MagicMock
 
 from bot import api
-from tests.helpers import async_test
 
 
-class APIClientTests(unittest.TestCase):
+class APIClientTests(unittest.IsolatedAsyncioTestCase):
     """Tests for the bot's API client."""
 
     @classmethod
@@ -14,15 +13,6 @@ class APIClientTests(unittest.TestCase):
         cls.error_api_response = MagicMock()
         cls.error_api_response.status = 999
 
-    def test_loop_is_not_running_by_default(self):
-        """The event loop should not be running by default."""
-        self.assertFalse(api.loop_is_running())
-
-    @async_test
-    async def test_loop_is_running_in_async_context(self):
-        """The event loop should be running in an async context."""
-        self.assertTrue(api.loop_is_running())
-
     def test_response_code_error_default_initialization(self):
         """Test the default initialization of `ResponseCodeError` without `text` or `json`"""
         error = api.ResponseCodeError(response=self.error_api_response)
diff --git a/tests/bot/test_constants.py b/tests/bot/test_constants.py
index dae7c066c..f10d6fbe8 100644
--- a/tests/bot/test_constants.py
+++ b/tests/bot/test_constants.py
@@ -1,14 +1,40 @@
 import inspect
+import typing
 import unittest
 
 from bot import constants
 
 
+def is_annotation_instance(value: typing.Any, annotation: typing.Any) -> bool:
+    """
+    Return True if `value` is an instance of the type represented by `annotation`.
+
+    This doesn't account for things like Unions or checking for homogenous types in collections.
+    """
+    origin = typing.get_origin(annotation)
+
+    # This is done in case a bare e.g. `typing.List` is used.
+    # In such case, for the assertion to pass, the type needs to be normalised to e.g. `list`.
+    # `get_origin()` does this normalisation for us.
+    type_ = annotation if origin is None else origin
+
+    return isinstance(value, type_)
+
+
+def is_any_instance(value: typing.Any, types: typing.Collection) -> bool:
+    """Return True if `value` is an instance of any type in `types`."""
+    for type_ in types:
+        if is_annotation_instance(value, type_):
+            return True
+
+    return False
+
+
 class ConstantsTests(unittest.TestCase):
     """Tests for our constants."""
 
     def test_section_configuration_matches_type_specification(self):
-        """The section annotations should match the actual types of the sections."""
+        """"The section annotations should match the actual types of the sections."""
 
         sections = (
             cls
@@ -17,10 +43,15 @@ class ConstantsTests(unittest.TestCase):
         )
         for section in sections:
             for name, annotation in section.__annotations__.items():
-                with self.subTest(section=section, name=name, annotation=annotation):
+                with self.subTest(section=section.__name__, name=name, annotation=annotation):
                     value = getattr(section, name)
+                    origin = typing.get_origin(annotation)
+                    annotation_args = typing.get_args(annotation)
+                    failure_msg = f"{value} is not an instance of {annotation}"
 
-                    if getattr(annotation, '_name', None) in ('Dict', 'List'):
-                        self.skipTest("Cannot validate containers yet.")
-
-                    self.assertIsInstance(value, annotation)
+                    if origin is typing.Union:
+                        is_instance = is_any_instance(value, annotation_args)
+                        self.assertTrue(is_instance, failure_msg)
+                    else:
+                        is_instance = is_annotation_instance(value, annotation)
+                        self.assertTrue(is_instance, failure_msg)
diff --git a/tests/bot/test_converters.py b/tests/bot/test_converters.py
index b2b78d9dd..c42111f3f 100644
--- a/tests/bot/test_converters.py
+++ b/tests/bot/test_converters.py
@@ -1,5 +1,5 @@
-import asyncio
 import datetime
+import re
 import unittest
 from unittest.mock import MagicMock, patch
 
@@ -8,6 +8,7 @@ from discord.ext.commands import BadArgument
 
 from bot.converters import (
     Duration,
+    HushDurationConverter,
     ISODateTime,
     TagContentConverter,
     TagNameConverter,
@@ -15,7 +16,7 @@ from bot.converters import (
 )
 
 
-class ConverterTests(unittest.TestCase):
+class ConverterTests(unittest.IsolatedAsyncioTestCase):
     """Tests our custom argument converters."""
 
     @classmethod
@@ -25,7 +26,7 @@ class ConverterTests(unittest.TestCase):
 
         cls.fixed_utc_now = datetime.datetime.fromisoformat('2019-01-01T00:00:00')
 
-    def test_tag_content_converter_for_valid(self):
+    async def test_tag_content_converter_for_valid(self):
         """TagContentConverter should return correct values for valid input."""
         test_values = (
             ('hello', 'hello'),
@@ -34,10 +35,10 @@ class ConverterTests(unittest.TestCase):
 
         for content, expected_conversion in test_values:
             with self.subTest(content=content, expected_conversion=expected_conversion):
-                conversion = asyncio.run(TagContentConverter.convert(self.context, content))
+                conversion = await TagContentConverter.convert(self.context, content)
                 self.assertEqual(conversion, expected_conversion)
 
-    def test_tag_content_converter_for_invalid(self):
+    async def test_tag_content_converter_for_invalid(self):
         """TagContentConverter should raise the proper exception for invalid input."""
         test_values = (
             ('', "Tag contents should not be empty, or filled with whitespace."),
@@ -46,10 +47,10 @@ class ConverterTests(unittest.TestCase):
 
         for value, exception_message in test_values:
             with self.subTest(tag_content=value, exception_message=exception_message):
-                with self.assertRaises(BadArgument, msg=exception_message):
-                    asyncio.run(TagContentConverter.convert(self.context, value))
+                with self.assertRaisesRegex(BadArgument, re.escape(exception_message)):
+                    await TagContentConverter.convert(self.context, value)
 
-    def test_tag_name_converter_for_valid(self):
+    async def test_tag_name_converter_for_valid(self):
         """TagNameConverter should return the correct values for valid tag names."""
         test_values = (
             ('tracebacks', 'tracebacks'),
@@ -59,44 +60,44 @@ class ConverterTests(unittest.TestCase):
 
         for name, expected_conversion in test_values:
             with self.subTest(name=name, expected_conversion=expected_conversion):
-                conversion = asyncio.run(TagNameConverter.convert(self.context, name))
+                conversion = await TagNameConverter.convert(self.context, name)
                 self.assertEqual(conversion, expected_conversion)
 
-    def test_tag_name_converter_for_invalid(self):
+    async def test_tag_name_converter_for_invalid(self):
         """TagNameConverter should raise the correct exception for invalid tag names."""
         test_values = (
             ('👋', "Don't be ridiculous, you can't use that character!"),
             ('', "Tag names should not be empty, or filled with whitespace."),
             ('  ', "Tag names should not be empty, or filled with whitespace."),
-            ('42', "Tag names can't be numbers."),
+            ('42', "Tag names must contain at least one letter."),
             ('x' * 128, "Are you insane? That's way too long!"),
         )
 
         for invalid_name, exception_message in test_values:
             with self.subTest(invalid_name=invalid_name, exception_message=exception_message):
-                with self.assertRaises(BadArgument, msg=exception_message):
-                    asyncio.run(TagNameConverter.convert(self.context, invalid_name))
+                with self.assertRaisesRegex(BadArgument, re.escape(exception_message)):
+                    await TagNameConverter.convert(self.context, invalid_name)
 
-    def test_valid_python_identifier_for_valid(self):
+    async def test_valid_python_identifier_for_valid(self):
         """ValidPythonIdentifier returns valid identifiers unchanged."""
         test_values = ('foo', 'lemon')
 
         for name in test_values:
             with self.subTest(identifier=name):
-                conversion = asyncio.run(ValidPythonIdentifier.convert(self.context, name))
+                conversion = await ValidPythonIdentifier.convert(self.context, name)
                 self.assertEqual(name, conversion)
 
-    def test_valid_python_identifier_for_invalid(self):
+    async def test_valid_python_identifier_for_invalid(self):
         """ValidPythonIdentifier raises the proper exception for invalid identifiers."""
         test_values = ('nested.stuff', '#####')
 
         for name in test_values:
             with self.subTest(identifier=name):
                 exception_message = f'`{name}` is not a valid Python identifier'
-                with self.assertRaises(BadArgument, msg=exception_message):
-                    asyncio.run(ValidPythonIdentifier.convert(self.context, name))
+                with self.assertRaisesRegex(BadArgument, re.escape(exception_message)):
+                    await ValidPythonIdentifier.convert(self.context, name)
 
-    def test_duration_converter_for_valid(self):
+    async def test_duration_converter_for_valid(self):
         """Duration returns the correct `datetime` for valid duration strings."""
         test_values = (
             # Simple duration strings
@@ -158,35 +159,35 @@ class ConverterTests(unittest.TestCase):
                 mock_datetime.utcnow.return_value = self.fixed_utc_now
 
                 with self.subTest(duration=duration, duration_dict=duration_dict):
-                    converted_datetime = asyncio.run(converter.convert(self.context, duration))
+                    converted_datetime = await converter.convert(self.context, duration)
                     self.assertEqual(converted_datetime, expected_datetime)
 
-    def test_duration_converter_for_invalid(self):
+    async def test_duration_converter_for_invalid(self):
         """Duration raises the right exception for invalid duration strings."""
         test_values = (
             # Units in wrong order
-            ('1d1w'),
-            ('1s1y'),
+            '1d1w',
+            '1s1y',
 
             # Duplicated units
-            ('1 year 2 years'),
-            ('1 M 10 minutes'),
+            '1 year 2 years',
+            '1 M 10 minutes',
 
             # Unknown substrings
-            ('1MVes'),
-            ('1y3breads'),
+            '1MVes',
+            '1y3breads',
 
             # Missing amount
-            ('ym'),
+            'ym',
 
             # Incorrect whitespace
-            (" 1y"),
-            ("1S "),
-            ("1y  1m"),
+            " 1y",
+            "1S ",
+            "1y  1m",
 
             # Garbage
-            ('Guido van Rossum'),
-            ('lemon lemon lemon lemon lemon lemon lemon'),
+            'Guido van Rossum',
+            'lemon lemon lemon lemon lemon lemon lemon',
         )
 
         converter = Duration()
@@ -194,10 +195,21 @@ class ConverterTests(unittest.TestCase):
         for invalid_duration in test_values:
             with self.subTest(invalid_duration=invalid_duration):
                 exception_message = f'`{invalid_duration}` is not a valid duration string.'
-                with self.assertRaises(BadArgument, msg=exception_message):
-                    asyncio.run(converter.convert(self.context, invalid_duration))
+                with self.assertRaisesRegex(BadArgument, re.escape(exception_message)):
+                    await converter.convert(self.context, invalid_duration)
 
-    def test_isodatetime_converter_for_valid(self):
+    @patch("bot.converters.datetime")
+    async def test_duration_converter_out_of_range(self, mock_datetime):
+        """Duration converter should raise BadArgument if datetime raises a ValueError."""
+        mock_datetime.__add__.side_effect = ValueError
+        mock_datetime.utcnow.return_value = mock_datetime
+
+        duration = f"{datetime.MAXYEAR}y"
+        exception_message = f"`{duration}` results in a datetime outside the supported range."
+        with self.assertRaisesRegex(BadArgument, re.escape(exception_message)):
+            await Duration().convert(self.context, duration)
+
+    async def test_isodatetime_converter_for_valid(self):
         """ISODateTime converter returns correct datetime for valid datetime string."""
         test_values = (
             # `YYYY-mm-ddTHH:MM:SSZ` | `YYYY-mm-dd HH:MM:SSZ`
@@ -242,32 +254,61 @@ class ConverterTests(unittest.TestCase):
 
         for datetime_string, expected_dt in test_values:
             with self.subTest(datetime_string=datetime_string, expected_dt=expected_dt):
-                converted_dt = asyncio.run(converter.convert(self.context, datetime_string))
+                converted_dt = await converter.convert(self.context, datetime_string)
                 self.assertIsNone(converted_dt.tzinfo)
                 self.assertEqual(converted_dt, expected_dt)
 
-    def test_isodatetime_converter_for_invalid(self):
+    async def test_isodatetime_converter_for_invalid(self):
         """ISODateTime converter raises the correct exception for invalid datetime strings."""
         test_values = (
             # Make sure it doesn't interfere with the Duration converter
-            ('1Y'),
-            ('1d'),
-            ('1H'),
+            '1Y',
+            '1d',
+            '1H',
 
             # Check if it fails when only providing the optional time part
-            ('10:10:10'),
-            ('10:00'),
+            '10:10:10',
+            '10:00',
 
             # Invalid date format
-            ('19-01-01'),
+            '19-01-01',
 
             # Other non-valid strings
-            ('fisk the tag master'),
+            'fisk the tag master',
         )
 
         converter = ISODateTime()
         for datetime_string in test_values:
             with self.subTest(datetime_string=datetime_string):
                 exception_message = f"`{datetime_string}` is not a valid ISO-8601 datetime string"
-                with self.assertRaises(BadArgument, msg=exception_message):
-                    asyncio.run(converter.convert(self.context, datetime_string))
+                with self.assertRaisesRegex(BadArgument, re.escape(exception_message)):
+                    await converter.convert(self.context, datetime_string)
+
+    async def test_hush_duration_converter_for_valid(self):
+        """HushDurationConverter returns correct value for minutes duration or `"forever"` strings."""
+        test_values = (
+            ("0", 0),
+            ("15", 15),
+            ("10", 10),
+            ("5m", 5),
+            ("5M", 5),
+            ("forever", None),
+        )
+        converter = HushDurationConverter()
+        for minutes_string, expected_minutes in test_values:
+            with self.subTest(minutes_string=minutes_string, expected_minutes=expected_minutes):
+                converted = await converter.convert(self.context, minutes_string)
+                self.assertEqual(expected_minutes, converted)
+
+    async def test_hush_duration_converter_for_invalid(self):
+        """HushDurationConverter raises correct exception for invalid minutes duration strings."""
+        test_values = (
+            ("16", "Duration must be at most 15 minutes."),
+            ("10d", "10d is not a valid minutes duration."),
+            ("-1", "-1 is not a valid minutes duration."),
+        )
+        converter = HushDurationConverter()
+        for invalid_minutes_string, exception_message in test_values:
+            with self.subTest(invalid_minutes_string=invalid_minutes_string, exception_message=exception_message):
+                with self.assertRaisesRegex(BadArgument, re.escape(exception_message)):
+                    await converter.convert(self.context, invalid_minutes_string)
diff --git a/tests/bot/test_decorators.py b/tests/bot/test_decorators.py
new file mode 100644
index 000000000..3d450caa0
--- /dev/null
+++ b/tests/bot/test_decorators.py
@@ -0,0 +1,147 @@
+import collections
+import unittest
+import unittest.mock
+
+from bot import constants
+from bot.decorators import in_whitelist
+from bot.utils.checks import InWhitelistCheckFailure
+from tests import helpers
+
+InWhitelistTestCase = collections.namedtuple("WhitelistedContextTestCase", ("kwargs", "ctx", "description"))
+
+
+class InWhitelistTests(unittest.TestCase):
+    """Tests for the `in_whitelist` check."""
+
+    @classmethod
+    def setUpClass(cls):
+        """Set up helpers that only need to be defined once."""
+        cls.bot_commands = helpers.MockTextChannel(id=123456789, category_id=123456)
+        cls.help_channel = helpers.MockTextChannel(id=987654321, category_id=987654)
+        cls.non_whitelisted_channel = helpers.MockTextChannel(id=666666)
+        cls.dm_channel = helpers.MockDMChannel()
+
+        cls.non_staff_member = helpers.MockMember()
+        cls.staff_role = helpers.MockRole(id=121212)
+        cls.staff_member = helpers.MockMember(roles=(cls.staff_role,))
+
+        cls.channels = (cls.bot_commands.id,)
+        cls.categories = (cls.help_channel.category_id,)
+        cls.roles = (cls.staff_role.id,)
+
+    def test_predicate_returns_true_for_whitelisted_context(self):
+        """The predicate should return `True` if a whitelisted context was passed to it."""
+        test_cases = (
+            InWhitelistTestCase(
+                kwargs={"channels": self.channels},
+                ctx=helpers.MockContext(channel=self.bot_commands, author=self.non_staff_member),
+                description="In whitelisted channels by members without whitelisted roles",
+            ),
+            InWhitelistTestCase(
+                kwargs={"redirect": self.bot_commands.id},
+                ctx=helpers.MockContext(channel=self.bot_commands, author=self.non_staff_member),
+                description="`redirect` should be implicitly added to `channels`",
+            ),
+            InWhitelistTestCase(
+                kwargs={"categories": self.categories},
+                ctx=helpers.MockContext(channel=self.help_channel, author=self.non_staff_member),
+                description="Whitelisted category without whitelisted role",
+            ),
+            InWhitelistTestCase(
+                kwargs={"roles": self.roles},
+                ctx=helpers.MockContext(channel=self.non_whitelisted_channel, author=self.staff_member),
+                description="Whitelisted role outside of whitelisted channel/category"
+            ),
+            InWhitelistTestCase(
+                kwargs={
+                    "channels": self.channels,
+                    "categories": self.categories,
+                    "roles": self.roles,
+                    "redirect": self.bot_commands,
+                },
+                ctx=helpers.MockContext(channel=self.help_channel, author=self.staff_member),
+                description="Case with all whitelist kwargs used",
+            ),
+        )
+
+        for test_case in test_cases:
+            # patch `commands.check` with a no-op lambda that just returns the predicate passed to it
+            # so we can test the predicate that was generated from the specified kwargs.
+            with unittest.mock.patch("bot.decorators.commands.check", new=lambda predicate: predicate):
+                predicate = in_whitelist(**test_case.kwargs)
+
+            with self.subTest(test_description=test_case.description):
+                self.assertTrue(predicate(test_case.ctx))
+
+    def test_predicate_raises_exception_for_non_whitelisted_context(self):
+        """The predicate should raise `InWhitelistCheckFailure` for a non-whitelisted context."""
+        test_cases = (
+            # Failing check with explicit `redirect`
+            InWhitelistTestCase(
+                kwargs={
+                    "categories": self.categories,
+                    "channels": self.channels,
+                    "roles": self.roles,
+                    "redirect": self.bot_commands.id,
+                },
+                ctx=helpers.MockContext(channel=self.non_whitelisted_channel, author=self.non_staff_member),
+                description="Failing check with an explicit redirect channel",
+            ),
+
+            # Failing check with implicit `redirect`
+            InWhitelistTestCase(
+                kwargs={
+                    "categories": self.categories,
+                    "channels": self.channels,
+                    "roles": self.roles,
+                },
+                ctx=helpers.MockContext(channel=self.non_whitelisted_channel, author=self.non_staff_member),
+                description="Failing check with an implicit redirect channel",
+            ),
+
+            # Failing check without `redirect`
+            InWhitelistTestCase(
+                kwargs={
+                    "categories": self.categories,
+                    "channels": self.channels,
+                    "roles": self.roles,
+                    "redirect": None,
+                },
+                ctx=helpers.MockContext(channel=self.non_whitelisted_channel, author=self.non_staff_member),
+                description="Failing check without a redirect channel",
+            ),
+
+            # Command issued in DM channel
+            InWhitelistTestCase(
+                kwargs={
+                    "categories": self.categories,
+                    "channels": self.channels,
+                    "roles": self.roles,
+                    "redirect": None,
+                },
+                ctx=helpers.MockContext(channel=self.dm_channel, author=self.dm_channel.me),
+                description="Commands issued in DM channel should be rejected",
+            ),
+        )
+
+        for test_case in test_cases:
+            if "redirect" not in test_case.kwargs or test_case.kwargs["redirect"] is not None:
+                # There are two cases in which we have a redirect channel:
+                #   1. No redirect channel was passed; the default value of `bot_commands` is used
+                #   2. An explicit `redirect` is set that is "not None"
+                redirect_channel = test_case.kwargs.get("redirect", constants.Channels.bot_commands)
+                redirect_message = f" here. Please use the <#{redirect_channel}> channel instead"
+            else:
+                # If an explicit `None` was passed for `redirect`, there is no redirect channel
+                redirect_message = ""
+
+            exception_message = f"You are not allowed to use that command{redirect_message}."
+
+            # patch `commands.check` with a no-op lambda that just returns the predicate passed to it
+            # so we can test the predicate that was generated from the specified kwargs.
+            with unittest.mock.patch("bot.decorators.commands.check", new=lambda predicate: predicate):
+                predicate = in_whitelist(**test_case.kwargs)
+
+            with self.subTest(test_description=test_case.description):
+                with self.assertRaisesRegex(InWhitelistCheckFailure, exception_message):
+                    predicate(test_case.ctx)
diff --git a/tests/bot/test_pagination.py b/tests/bot/test_pagination.py
index 0a734b505..630f2516d 100644
--- a/tests/bot/test_pagination.py
+++ b/tests/bot/test_pagination.py
@@ -8,29 +8,39 @@ class LinePaginatorTests(TestCase):
 
     def setUp(self):
         """Create a paginator for the test method."""
-        self.paginator = pagination.LinePaginator(prefix='', suffix='', max_size=30)
-
-    def test_add_line_raises_on_too_long_lines(self):
-        """`add_line` should raise a `RuntimeError` for too long lines."""
-        message = f"Line exceeds maximum page size {self.paginator.max_size - 2}"
-        with self.assertRaises(RuntimeError, msg=message):
-            self.paginator.add_line('x' * self.paginator.max_size)
+        self.paginator = pagination.LinePaginator(prefix='', suffix='', max_size=30,
+                                                  scale_to_size=50)
 
     def test_add_line_works_on_small_lines(self):
         """`add_line` should allow small lines to be added."""
         self.paginator.add_line('x' * (self.paginator.max_size - 3))
-
-
-class ImagePaginatorTests(TestCase):
-    """Tests functionality of the `ImagePaginator`."""
-
-    def setUp(self):
-        """Create a paginator for the test method."""
-        self.paginator = pagination.ImagePaginator()
-
-    def test_add_image_appends_image(self):
-        """`add_image` appends the image to the image list."""
-        image = 'lemon'
-        self.paginator.add_image(image)
-
-        assert self.paginator.images == [image]
+        # Note that the page isn't added to _pages until it's full.
+        self.assertEqual(len(self.paginator._pages), 0)
+
+    def test_add_line_works_on_long_lines(self):
+        """After additional lines after `max_size` is exceeded should go on the next page."""
+        self.paginator.add_line('x' * self.paginator.max_size)
+        self.assertEqual(len(self.paginator._pages), 0)
+
+        # Any additional lines should start a new page after `max_size` is exceeded.
+        self.paginator.add_line('x')
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_continuation(self):
+        """When `scale_to_size` is exceeded, remaining words should be split onto the next page."""
+        self.paginator.add_line('zyz ' * (self.paginator.scale_to_size//4 + 1))
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_no_continuation(self):
+        """If adding a new line to an existing page would exceed `max_size`, it should start a new
+        page rather than using continuation.
+        """
+        self.paginator.add_line('z' * (self.paginator.max_size - 3))
+        self.paginator.add_line('z')
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_truncates_very_long_words(self):
+        """`add_line` should truncate if a single long word exceeds `scale_to_size`."""
+        self.paginator.add_line('x' * (self.paginator.scale_to_size + 1))
+        # Note: item at index 1 is the truncated line, index 0 is prefix
+        self.assertEqual(self.paginator._current_page[1], 'x' * self.paginator.scale_to_size)
diff --git a/tests/bot/test_utils.py b/tests/bot/test_utils.py
deleted file mode 100644
index 58ae2a81a..000000000
--- a/tests/bot/test_utils.py
+++ /dev/null
@@ -1,52 +0,0 @@
-import unittest
-
-from bot import utils
-
-
-class CaseInsensitiveDictTests(unittest.TestCase):
-    """Tests for the `CaseInsensitiveDict` container."""
-
-    def test_case_insensitive_key_access(self):
-        """Tests case insensitive key access and storage."""
-        instance = utils.CaseInsensitiveDict()
-
-        key = 'LEMON'
-        value = 'trees'
-
-        instance[key] = value
-        self.assertIn(key, instance)
-        self.assertEqual(instance.get(key), value)
-        self.assertEqual(instance.get(key.casefold()), value)
-        self.assertEqual(instance.pop(key.casefold()), value)
-        self.assertNotIn(key, instance)
-        self.assertNotIn(key.casefold(), instance)
-
-        instance.setdefault(key, value)
-        del instance[key]
-        self.assertNotIn(key, instance)
-
-    def test_initialization_from_kwargs(self):
-        """Tests creating the dictionary from keyword arguments."""
-        instance = utils.CaseInsensitiveDict({'FOO': 'bar'})
-        self.assertEqual(instance['foo'], 'bar')
-
-    def test_update_from_other_mapping(self):
-        """Tests updating the dictionary from another mapping."""
-        instance = utils.CaseInsensitiveDict()
-        instance.update({'FOO': 'bar'})
-        self.assertEqual(instance['foo'], 'bar')
-
-
-class ChunkTests(unittest.TestCase):
-    """Tests the `chunk` method."""
-
-    def test_empty_chunking(self):
-        """Tests chunking on an empty iterable."""
-        generator = utils.chunks(iterable=[], size=5)
-        self.assertEqual(list(generator), [])
-
-    def test_list_chunking(self):
-        """Tests chunking a non-empty list."""
-        iterable = [1, 2, 3, 4, 5]
-        generator = utils.chunks(iterable=iterable, size=2)
-        self.assertEqual(list(generator), [[1, 2], [3, 4], [5]])
diff --git a/tests/bot/utils/test_checks.py b/tests/bot/utils/test_checks.py
index 9610771e5..883465e0b 100644
--- a/tests/bot/utils/test_checks.py
+++ b/tests/bot/utils/test_checks.py
@@ -1,51 +1,93 @@
 import unittest
+from unittest.mock import MagicMock
+
+from discord import DMChannel
 
 from bot.utils import checks
+from bot.utils.checks import InWhitelistCheckFailure
 from tests.helpers import MockContext, MockRole
 
 
-class ChecksTests(unittest.TestCase):
+class ChecksTests(unittest.IsolatedAsyncioTestCase):
     """Tests the check functions defined in `bot.checks`."""
 
     def setUp(self):
         self.ctx = MockContext()
 
-    def test_with_role_check_without_guild(self):
-        """`with_role_check` returns `False` if `Context.guild` is None."""
-        self.ctx.guild = None
-        self.assertFalse(checks.with_role_check(self.ctx))
+    async def test_has_any_role_check_without_guild(self):
+        """`has_any_role_check` returns `False` for non-guild channels."""
+        self.ctx.channel = MagicMock(DMChannel)
+        self.assertFalse(await checks.has_any_role_check(self.ctx))
 
-    def test_with_role_check_without_required_roles(self):
-        """`with_role_check` returns `False` if `Context.author` lacks the required role."""
+    async def test_has_any_role_check_without_required_roles(self):
+        """`has_any_role_check` returns `False` if `Context.author` lacks the required role."""
         self.ctx.author.roles = []
-        self.assertFalse(checks.with_role_check(self.ctx))
+        self.assertFalse(await checks.has_any_role_check(self.ctx))
 
-    def test_with_role_check_with_guild_and_required_role(self):
-        """`with_role_check` returns `True` if `Context.author` has the required role."""
+    async def test_has_any_role_check_with_guild_and_required_role(self):
+        """`has_any_role_check` returns `True` if `Context.author` has the required role."""
         self.ctx.author.roles.append(MockRole(id=10))
-        self.assertTrue(checks.with_role_check(self.ctx, 10))
+        self.assertTrue(await checks.has_any_role_check(self.ctx, 10))
 
-    def test_without_role_check_without_guild(self):
-        """`without_role_check` should return `False` when `Context.guild` is None."""
-        self.ctx.guild = None
-        self.assertFalse(checks.without_role_check(self.ctx))
+    async def test_has_no_roles_check_without_guild(self):
+        """`has_no_roles_check` should return `False` when `Context.guild` is None."""
+        self.ctx.channel = MagicMock(DMChannel)
+        self.assertFalse(await checks.has_no_roles_check(self.ctx))
 
-    def test_without_role_check_returns_false_with_unwanted_role(self):
-        """`without_role_check` returns `False` if `Context.author` has unwanted role."""
+    async def test_has_no_roles_check_returns_false_with_unwanted_role(self):
+        """`has_no_roles_check` returns `False` if `Context.author` has unwanted role."""
         role_id = 42
         self.ctx.author.roles.append(MockRole(id=role_id))
-        self.assertFalse(checks.without_role_check(self.ctx, role_id))
+        self.assertFalse(await checks.has_no_roles_check(self.ctx, role_id))
 
-    def test_without_role_check_returns_true_without_unwanted_role(self):
-        """`without_role_check` returns `True` if `Context.author` does not have unwanted role."""
+    async def test_has_no_roles_check_returns_true_without_unwanted_role(self):
+        """`has_no_roles_check` returns `True` if `Context.author` does not have unwanted role."""
         role_id = 42
         self.ctx.author.roles.append(MockRole(id=role_id))
-        self.assertTrue(checks.without_role_check(self.ctx, role_id + 10))
+        self.assertTrue(await checks.has_no_roles_check(self.ctx, role_id + 10))
+
+    def test_in_whitelist_check_correct_channel(self):
+        """`in_whitelist_check` returns `True` if `Context.channel.id` is in the channel list."""
+        channel_id = 3
+        self.ctx.channel.id = channel_id
+        self.assertTrue(checks.in_whitelist_check(self.ctx, [channel_id]))
+
+    def test_in_whitelist_check_incorrect_channel(self):
+        """`in_whitelist_check` raises InWhitelistCheckFailure if there's no channel match."""
+        self.ctx.channel.id = 3
+        with self.assertRaises(InWhitelistCheckFailure):
+            checks.in_whitelist_check(self.ctx, [4])
+
+    def test_in_whitelist_check_correct_category(self):
+        """`in_whitelist_check` returns `True` if `Context.channel.category_id` is in the category list."""
+        category_id = 3
+        self.ctx.channel.category_id = category_id
+        self.assertTrue(checks.in_whitelist_check(self.ctx, categories=[category_id]))
+
+    def test_in_whitelist_check_incorrect_category(self):
+        """`in_whitelist_check` raises InWhitelistCheckFailure if there's no category match."""
+        self.ctx.channel.category_id = 3
+        with self.assertRaises(InWhitelistCheckFailure):
+            checks.in_whitelist_check(self.ctx, categories=[4])
+
+    def test_in_whitelist_check_correct_role(self):
+        """`in_whitelist_check` returns `True` if any of the `Context.author.roles` are in the roles list."""
+        self.ctx.author.roles = (MagicMock(id=1), MagicMock(id=2))
+        self.assertTrue(checks.in_whitelist_check(self.ctx, roles=[2, 6]))
+
+    def test_in_whitelist_check_incorrect_role(self):
+        """`in_whitelist_check` raises InWhitelistCheckFailure if there's no role match."""
+        self.ctx.author.roles = (MagicMock(id=1), MagicMock(id=2))
+        with self.assertRaises(InWhitelistCheckFailure):
+            checks.in_whitelist_check(self.ctx, roles=[4])
 
-    def test_in_channel_check_for_correct_channel(self):
-        self.ctx.channel.id = 42
-        self.assertTrue(checks.in_channel_check(self.ctx, *[42]))
+    def test_in_whitelist_check_fail_silently(self):
+        """`in_whitelist_check` test no exception raised if `fail_silently` is `True`"""
+        self.assertFalse(checks.in_whitelist_check(self.ctx, roles=[2, 6], fail_silently=True))
 
-    def test_in_channel_check_for_incorrect_channel(self):
-        self.ctx.channel.id = 42 + 10
-        self.assertFalse(checks.in_channel_check(self.ctx, *[42]))
+    def test_in_whitelist_check_complex(self):
+        """`in_whitelist_check` test with multiple parameters"""
+        self.ctx.author.roles = (MagicMock(id=1), MagicMock(id=2))
+        self.ctx.channel.category_id = 3
+        self.ctx.channel.id = 5
+        self.assertTrue(checks.in_whitelist_check(self.ctx, channels=[1], categories=[8], roles=[2]))
diff --git a/tests/bot/utils/test_messages.py b/tests/bot/utils/test_messages.py
new file mode 100644
index 000000000..9c22c9751
--- /dev/null
+++ b/tests/bot/utils/test_messages.py
@@ -0,0 +1,27 @@
+import unittest
+
+from bot.utils import messages
+
+
+class TestMessages(unittest.TestCase):
+    """Tests for functions in the `bot.utils.messages` module."""
+
+    def test_sub_clyde(self):
+        """Uppercase E's and lowercase e's are substituted with their cyrillic counterparts."""
+        sub_e = "\u0435"
+        sub_E = "\u0415"  # noqa: N806: Uppercase E in variable name
+
+        test_cases = (
+            (None, None),
+            ("", ""),
+            ("clyde", f"clyd{sub_e}"),
+            ("CLYDE", f"CLYD{sub_E}"),
+            ("cLyDe", f"cLyD{sub_e}"),
+            ("BIGclyde", f"BIGclyd{sub_e}"),
+            ("small clydeus the unholy", f"small clyd{sub_e}us the unholy"),
+            ("BIGCLYDE, babyclyde", f"BIGCLYD{sub_E}, babyclyd{sub_e}"),
+        )
+
+        for username_in, username_out in test_cases:
+            with self.subTest(input=username_in, expected_output=username_out):
+                self.assertEqual(messages.sub_clyde(username_in), username_out)
diff --git a/tests/bot/utils/test_services.py b/tests/bot/utils/test_services.py
new file mode 100644
index 000000000..1b48f6560
--- /dev/null
+++ b/tests/bot/utils/test_services.py
@@ -0,0 +1,77 @@
+import logging
+import unittest
+from unittest.mock import AsyncMock, MagicMock, Mock, patch
+
+from aiohttp import ClientConnectorError
+
+from bot.utils.services import FAILED_REQUEST_ATTEMPTS, send_to_paste_service
+from tests.helpers import MockBot
+
+
+class PasteTests(unittest.IsolatedAsyncioTestCase):
+    def setUp(self) -> None:
+        patcher = patch("bot.instance", new=MockBot())
+        self.bot = patcher.start()
+        self.addCleanup(patcher.stop)
+
+    @patch("bot.utils.services.URLs.paste_service", "https://paste_service.com/{key}")
+    async def test_url_and_sent_contents(self):
+        """Correct url was used and post was called with expected data."""
+        response = MagicMock(
+            json=AsyncMock(return_value={"key": ""})
+        )
+        self.bot.http_session.post.return_value.__aenter__.return_value = response
+        self.bot.http_session.post.reset_mock()
+        await send_to_paste_service("Content")
+        self.bot.http_session.post.assert_called_once_with("https://paste_service.com/documents", data="Content")
+
+    @patch("bot.utils.services.URLs.paste_service", "https://paste_service.com/{key}")
+    async def test_paste_returns_correct_url_on_success(self):
+        """Url with specified extension is returned on successful requests."""
+        key = "paste_key"
+        test_cases = (
+            (f"https://paste_service.com/{key}.txt", "txt"),
+            (f"https://paste_service.com/{key}.py", "py"),
+            (f"https://paste_service.com/{key}", ""),
+        )
+        response = MagicMock(
+            json=AsyncMock(return_value={"key": key})
+        )
+        self.bot.http_session.post.return_value.__aenter__.return_value = response
+
+        for expected_output, extension in test_cases:
+            with self.subTest(msg=f"Send contents with extension {repr(extension)}"):
+                self.assertEqual(
+                    await send_to_paste_service("", extension=extension),
+                    expected_output
+                )
+
+    async def test_request_repeated_on_json_errors(self):
+        """Json with error message and invalid json are handled as errors and requests repeated."""
+        test_cases = ({"message": "error"}, {"unexpected_key": None}, {})
+        self.bot.http_session.post.return_value.__aenter__.return_value = response = MagicMock()
+        self.bot.http_session.post.reset_mock()
+
+        for error_json in test_cases:
+            with self.subTest(error_json=error_json):
+                response.json = AsyncMock(return_value=error_json)
+                result = await send_to_paste_service("")
+                self.assertEqual(self.bot.http_session.post.call_count, FAILED_REQUEST_ATTEMPTS)
+                self.assertIsNone(result)
+
+            self.bot.http_session.post.reset_mock()
+
+    async def test_request_repeated_on_connection_errors(self):
+        """Requests are repeated in the case of connection errors."""
+        self.bot.http_session.post = MagicMock(side_effect=ClientConnectorError(Mock(), Mock()))
+        result = await send_to_paste_service("")
+        self.assertEqual(self.bot.http_session.post.call_count, FAILED_REQUEST_ATTEMPTS)
+        self.assertIsNone(result)
+
+    async def test_general_error_handled_and_request_repeated(self):
+        """All `Exception`s are handled, logged and request repeated."""
+        self.bot.http_session.post = MagicMock(side_effect=Exception)
+        result = await send_to_paste_service("")
+        self.assertEqual(self.bot.http_session.post.call_count, FAILED_REQUEST_ATTEMPTS)
+        self.assertLogs("bot.utils", logging.ERROR)
+        self.assertIsNone(result)
diff --git a/tests/bot/utils/test_time.py b/tests/bot/utils/test_time.py
index 69f35f2f5..694d3a40f 100644
--- a/tests/bot/utils/test_time.py
+++ b/tests/bot/utils/test_time.py
@@ -1,12 +1,11 @@
 import asyncio
 import unittest
 from datetime import datetime, timezone
-from unittest.mock import patch
+from unittest.mock import AsyncMock, patch
 
 from dateutil.relativedelta import relativedelta
 
 from bot.utils import time
-from tests.helpers import AsyncMock
 
 
 class TimeTests(unittest.TestCase):
@@ -44,7 +43,7 @@ class TimeTests(unittest.TestCase):
         for max_units in test_cases:
             with self.subTest(max_units=max_units), self.assertRaises(ValueError) as error:
                 time.humanize_delta(relativedelta(days=2, hours=2), 'hours', max_units)
-                self.assertEqual(str(error), 'max_units must be positive')
+            self.assertEqual(str(error.exception), 'max_units must be positive')
 
     def test_parse_rfc1123(self):
         """Testing parse_rfc1123."""