Merge branch 'master' into logging-tests

17 files changed, 1047 insertions, 200 deletions

diff --git a/tests/bot/cogs/moderation/test_infractions.py b/tests/bot/cogs/moderation/test_infractions.py
new file mode 100644
index 000000000..da4e92ccc
--- /dev/null
+++ b/tests/bot/cogs/moderation/test_infractions.py
@@ -0,0 +1,55 @@
+import textwrap
+import unittest
+from unittest.mock import AsyncMock, Mock, patch
+
+from bot.cogs.moderation.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.cogs.moderation.utils.get_active_infraction")
+    @patch("bot.cogs.moderation.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.cogs.moderation.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
+        )
diff --git a/tests/bot/cogs/moderation/test_modlog.py b/tests/bot/cogs/moderation/test_modlog.py
new file mode 100644
index 000000000..f2809f40a
--- /dev/null
+++ b/tests/bot/cogs/moderation/test_modlog.py
@@ -0,0 +1,29 @@
+import unittest
+
+import discord
+
+from bot.cogs.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/cogs/moderation/test_silence.py b/tests/bot/cogs/moderation/test_silence.py
index 3fd149f04..ab3d0742a 100644
--- a/tests/bot/cogs/moderation/test_silence.py
+++ b/tests/bot/cogs/moderation/test_silence.py
@@ -127,10 +127,20 @@ class SilenceTests(unittest.IsolatedAsyncioTestCase):
             self.ctx.reset_mock()
 
     async def test_unsilence_sent_correct_discord_message(self):
-        """Proper reply after a successful unsilence."""
-        with mock.patch.object(self.cog, "_unsilence", return_value=True):
-            await self.cog.unsilence.callback(self.cog, self.ctx)
-            self.ctx.send.assert_called_once_with(f"{Emojis.check_mark} unsilenced current channel.")
+        """Check if proper message was sent when unsilencing channel."""
+        test_cases = (
+            (True, f"{Emojis.check_mark} unsilenced current channel."),
+            (False, f"{Emojis.cross_mark} current channel was not silenced.")
+        )
+        for _unsilence_patch_return, result_message in test_cases:
+            with self.subTest(
+                starting_silenced_state=_unsilence_patch_return,
+                result_message=result_message
+            ):
+                with mock.patch.object(self.cog, "_unsilence", return_value=_unsilence_patch_return):
+                    await self.cog.unsilence.callback(self.cog, self.ctx)
+                    self.ctx.send.assert_called_once_with(result_message)
+            self.ctx.reset_mock()
 
     async def test_silence_private_for_false(self):
         """Permissions are not set and `False` is returned in an already silenced channel."""
diff --git a/tests/bot/cogs/sync/test_cog.py b/tests/bot/cogs/sync/test_cog.py
index 81398c61f..14fd909c4 100644
--- a/tests/bot/cogs/sync/test_cog.py
+++ b/tests/bot/cogs/sync/test_cog.py
@@ -247,14 +247,12 @@ class SyncCogListenerTests(SyncCogTestCase):
         before_data = {
             "name": "old name",
             "discriminator": "1234",
-            "avatar": "old avatar",
             "bot": False,
         }
 
         subtests = (
             (True, "name", "name", "new name", "new name"),
             (True, "discriminator", "discriminator", "8765", 8765),
-            (True, "avatar", "avatar_hash", "9j2e9", "9j2e9"),
             (False, "bot", "bot", True, True),
         )
 
@@ -295,7 +293,6 @@ class SyncCogListenerTests(SyncCogTestCase):
         )
 
         data = {
-            "avatar_hash": member.avatar,
             "discriminator": int(member.discriminator),
             "id": member.id,
             "in_guild": True,
diff --git a/tests/bot/cogs/sync/test_users.py b/tests/bot/cogs/sync/test_users.py
index 818883012..002a947ad 100644
--- a/tests/bot/cogs/sync/test_users.py
+++ b/tests/bot/cogs/sync/test_users.py
@@ -10,7 +10,6 @@ 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)
 
@@ -32,7 +31,6 @@ class UserSyncerDiffTests(unittest.IsolatedAsyncioTestCase):
 
         for member in members:
             member = member.copy()
-            member["avatar"] = member.pop("avatar_hash")
             del member["in_guild"]
 
             mock_member = helpers.MockMember(**member)
diff --git a/tests/bot/cogs/test_antimalware.py b/tests/bot/cogs/test_antimalware.py
new file mode 100644
index 000000000..f219fc1ba
--- /dev/null
+++ b/tests/bot/cogs/test_antimalware.py
@@ -0,0 +1,159 @@
+import unittest
+from unittest.mock import AsyncMock, Mock, patch
+
+from discord import NotFound
+
+from bot.cogs import antimalware
+from bot.constants import AntiMalware as AntiMalwareConfig, Channels, STAFF_ROLES
+from tests.helpers import MockAttachment, MockBot, MockMessage, MockRole
+
+MODULE = "bot.cogs.antimalware"
+
+
+@patch(f"{MODULE}.AntiMalwareConfig.whitelist", new=[".first", ".second", ".third"])
+class AntiMalwareCogTests(unittest.IsolatedAsyncioTestCase):
+    """Test the AntiMalware cog."""
+
+    def setUp(self):
+        """Sets up fresh objects for each test."""
+        self.bot = MockBot()
+        self.cog = antimalware.AntiMalware(self.bot)
+        self.message = MockMessage()
+
+    async def test_message_with_allowed_attachment(self):
+        """Messages with allowed extensions should not be deleted"""
+        attachment = MockAttachment(filename=f"python{AntiMalwareConfig.whitelist[0]}")
+        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_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_extention_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(
+            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 = (
+            ([], []),
+            (AntiMalwareConfig.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_duck_pond.py b/tests/bot/cogs/test_duck_pond.py
index 7e6bfc748..a8c0107c6 100644
--- a/tests/bot/cogs/test_duck_pond.py
+++ b/tests/bot/cogs/test_duck_pond.py
@@ -45,7 +45,7 @@ class DuckPondTests(base.LoggingTestsMixin, unittest.IsolatedAsyncioTestCase):
 
         self.assertEqual(cog.bot, bot)
         self.assertEqual(cog.webhook_id, constants.Webhooks.duck_pond)
-        bot.loop.create_loop.called_once_with(cog.fetch_webhook())
+        bot.loop.create_task.assert_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."""
diff --git a/tests/bot/cogs/test_information.py b/tests/bot/cogs/test_information.py
index b5f928dd6..79c0e0ad3 100644
--- a/tests/bot/cogs/test_information.py
+++ b/tests/bot/cogs/test_information.py
@@ -7,10 +7,9 @@ import discord
 
 from bot import constants
 from bot.cogs import information
-from bot.decorators import InWhitelistCheckFailure
+from bot.utils.checks import InWhitelistCheckFailure
 from tests import helpers
 
-
 COG_PATH = "bot.cogs.information.Information"
 
 
@@ -149,14 +148,18 @@ class InformationCogTests(unittest.TestCase):
                 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)}
+                **Channel counts**
                 Category channels: 1
                 Text channels: 1
                 Voice channels: 1
+                Staff channels: 0
+
+                **Member counts**
+                Members: {self.ctx.guild.member_count:,}
+                Staff members: 0
+                Roles: {len(self.ctx.guild.roles)}
 
-                **Members**
+                **Member statuses**
                 {constants.Emojis.status_online} 2
                 {constants.Emojis.status_idle} 1
                 {constants.Emojis.status_dnd} 4
diff --git a/tests/bot/cogs/test_snekbox.py b/tests/bot/cogs/test_snekbox.py
index 8490b02ca..cf9adbee0 100644
--- a/tests/bot/cogs/test_snekbox.py
+++ b/tests/bot/cogs/test_snekbox.py
@@ -21,7 +21,10 @@ class SnekboxTests(unittest.IsolatedAsyncioTestCase):
         """Post the eval code to the URLs.snekbox_eval_api endpoint."""
         resp = MagicMock()
         resp.json = AsyncMock(return_value="return")
-        self.bot.http_session.post().__aenter__.return_value = resp
+
+        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(
@@ -41,7 +44,10 @@ class SnekboxTests(unittest.IsolatedAsyncioTestCase):
         key = "MarkDiamond"
         resp = MagicMock()
         resp.json = AsyncMock(return_value={"key": key})
-        self.bot.http_session.post().__aenter__.return_value = resp
+
+        context_manager = MagicMock()
+        context_manager.__aenter__.return_value = resp
+        self.bot.http_session.post.return_value = context_manager
 
         self.assertEqual(
             await self.cog.upload_output("My awesome output"),
@@ -57,7 +63,10 @@ class SnekboxTests(unittest.IsolatedAsyncioTestCase):
         """Output upload gracefully fallback if the upload fail."""
         resp = MagicMock()
         resp.json = AsyncMock(side_effect=Exception)
-        self.bot.http_session.post().__aenter__.return_value = resp
+
+        context_manager = MagicMock()
+        context_manager.__aenter__.return_value = resp
+        self.bot.http_session.post.return_value = context_manager
 
         log = logging.getLogger("bot.cogs.snekbox")
         with self.assertLogs(logger=log, level='ERROR'):
@@ -290,7 +299,11 @@ class SnekboxTests(unittest.IsolatedAsyncioTestCase):
         self.assertEqual(actual, expected)
         self.bot.wait_for.assert_has_awaits(
             (
-                call('message_edit', check=partial_mock(snekbox.predicate_eval_message_edit, ctx), timeout=10),
+                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)
             )
         )
diff --git a/tests/bot/cogs/test_token_remover.py b/tests/bot/cogs/test_token_remover.py
index 33d1ec170..3349caa73 100644
--- a/tests/bot/cogs/test_token_remover.py
+++ b/tests/bot/cogs/test_token_remover.py
@@ -1,56 +1,89 @@
-import asyncio
-import logging
 import unittest
-from unittest.mock import AsyncMock, MagicMock
+from re import Match
+from unittest import mock
+from unittest.mock import MagicMock
 
-from discord import Colour
+from discord import Colour, NotFound
 
-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 MockBot, MockMessage
+from bot import constants
+from bot.cogs import token_remover
+from bot.cogs.moderation import ModLog
+from bot.cogs.token_remover import Token, TokenRemover
+from tests.helpers import MockBot, MockMessage, autospec
 
 
-class TokenRemoverTests(unittest.TestCase):
+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.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 = MockMessage(id=555, content="hello world")
         self.msg.channel.mention = "#lemonade-stand"
+        self.msg.author.__str__ = MagicMock(return_value=self.msg.author.name)
+        self.msg.author.avatar_url_as.return_value = "picture-lemon.png"
 
-    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_valid(self):
+        """Should consider user IDs valid if they decode entirely to ASCII digits."""
+        ids = (
+            "NDcyMjY1OTQzMDYyNDEzMzMy",
+            "NDc1MDczNjI5Mzk5NTQ3OTA0",
+            "NDY3MjIzMjMwNjUwNzc3NjQx",
+        )
+
+        for user_id in ids:
+            with self.subTest(user_id=user_id):
+                result = TokenRemover.is_valid_user_id(user_id)
+                self.assertTrue(result)
 
-    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_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"),
+        )
 
-    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'))
+        for user_id, msg in ids:
+            with self.subTest(msg=msg):
+                result = TokenRemover.is_valid_user_id(user_id)
+                self.assertFalse(result)
 
-    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_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_mod_log_property(self):
         """The `mod_log` property should ask the bot to return the `ModLog` cog."""
@@ -58,74 +91,220 @@ class TokenRemoverTests(unittest.TestCase):
         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'),
+    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.cogs.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, "is_valid_user_id", "is_valid_timestamp")
+    @autospec("bot.cogs.token_remover", "Token")
+    @autospec("bot.cogs.token_remover", "TOKEN_RE")
+    def test_find_token_valid_match(self, token_re, token_cls, is_valid_id, is_valid_timestamp):
+        """The first match with a valid user ID and timestamp 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
+        is_valid_id.side_effect = (False, True)  # The 1st match will be invalid, 2nd one valid.
+        is_valid_timestamp.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, "is_valid_user_id", "is_valid_timestamp")
+    @autospec("bot.cogs.token_remover", "Token")
+    @autospec("bot.cogs.token_remover", "TOKEN_RE")
+    def test_find_token_invalid_matches(self, token_re, token_cls, is_valid_id, is_valid_timestamp):
+        """None should be returned if no matches have valid user IDs or 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)
+        is_valid_id.return_value = False
+        is_valid_timestamp.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.cogs.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("NDY3MjIzMjMwNjUwNzc3NjQx", "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=self.msg.author,
+            author_id=self.msg.author.id,
+            channel=self.msg.channel.mention,
+            user_id=token.user_id,
+            timestamp=token.timestamp,
+            hmac="x" * len(token.hmac),
+        )
+
+    @mock.patch.object(TokenRemover, "mod_log", new_callable=mock.PropertyMock)
+    @autospec("bot.cogs.token_remover", "log")
+    @autospec(TokenRemover, "format_log_message")
+    async def test_take_action(self, format_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)
+        log_msg = "testing123"
+
+        mod_log_property.return_value = mod_log
+        format_log_message.return_value = log_msg
+
+        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)
+        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,
+            thumbnail=self.msg.author.avatar_url_as.return_value,
+            channel_id=constants.Channels.mod_alerts
         )
 
-        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."""
+    @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.cogs.token_remover", "TokenRemover")
+    def test_extension_setup(self, cog):
+        """The TokenRemover cog should be added."""
         bot = MockBot()
-        setup_cog(bot)
+        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/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 ca8cb6825..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
 
@@ -16,7 +16,7 @@ from bot.converters import (
 )
 
 
-class ConverterTests(unittest.TestCase):
+class ConverterTests(unittest.IsolatedAsyncioTestCase):
     """Tests our custom argument converters."""
 
     @classmethod
@@ -26,7 +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'),
@@ -35,10 +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."),
@@ -47,10 +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'),
@@ -60,10 +60,10 @@ 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!"),
@@ -75,29 +75,29 @@ class ConverterTests(unittest.TestCase):
 
         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
@@ -159,35 +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()
@@ -195,10 +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`
@@ -243,37 +254,37 @@ 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)
 
-    def test_hush_duration_converter_for_valid(self):
+    async def test_hush_duration_converter_for_valid(self):
         """HushDurationConverter returns correct value for minutes duration or `"forever"` strings."""
         test_values = (
             ("0", 0),
@@ -286,10 +297,10 @@ class ConverterTests(unittest.TestCase):
         converter = HushDurationConverter()
         for minutes_string, expected_minutes in test_values:
             with self.subTest(minutes_string=minutes_string, expected_minutes=expected_minutes):
-                converted = asyncio.run(converter.convert(self.context, minutes_string))
+                converted = await converter.convert(self.context, minutes_string)
                 self.assertEqual(expected_minutes, converted)
 
-    def test_hush_duration_converter_for_invalid(self):
+    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."),
@@ -299,5 +310,5 @@ class ConverterTests(unittest.TestCase):
         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, exception_message):
-                    asyncio.run(converter.convert(self.context, invalid_minutes_string))
+                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
index a17dd3e16..3d450caa0 100644
--- a/tests/bot/test_decorators.py
+++ b/tests/bot/test_decorators.py
@@ -3,10 +3,10 @@ import unittest
 import unittest.mock
 
 from bot import constants
-from bot.decorators import InWhitelistCheckFailure, in_whitelist
+from bot.decorators import in_whitelist
+from bot.utils.checks import InWhitelistCheckFailure
 from tests import helpers
 
-
 InWhitelistTestCase = collections.namedtuple("WhitelistedContextTestCase", ("kwargs", "ctx", "description"))
 
 
diff --git a/tests/bot/utils/test_checks.py b/tests/bot/utils/test_checks.py
index 9610771e5..de72e5748 100644
--- a/tests/bot/utils/test_checks.py
+++ b/tests/bot/utils/test_checks.py
@@ -1,6 +1,8 @@
 import unittest
+from unittest.mock import MagicMock
 
 from bot.utils import checks
+from bot.utils.checks import InWhitelistCheckFailure
 from tests.helpers import MockContext, MockRole
 
 
@@ -42,10 +44,48 @@ class ChecksTests(unittest.TestCase):
         self.ctx.author.roles.append(MockRole(id=role_id))
         self.assertTrue(checks.without_role_check(self.ctx, role_id + 10))
 
-    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_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_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_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_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_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_redis_cache.py b/tests/bot/utils/test_redis_cache.py
new file mode 100644
index 000000000..a2f0fe55d
--- /dev/null
+++ b/tests/bot/utils/test_redis_cache.py
@@ -0,0 +1,265 @@
+import asyncio
+import unittest
+
+import fakeredis.aioredis
+
+from bot.utils import RedisCache
+from bot.utils.redis_cache import NoBotInstanceError, NoNamespaceError, NoParentInstanceError
+from tests import helpers
+
+
+class RedisCacheTests(unittest.IsolatedAsyncioTestCase):
+    """Tests the RedisCache class from utils.redis_dict.py."""
+
+    async def asyncSetUp(self):  # noqa: N802
+        """Sets up the objects that only have to be initialized once."""
+        self.bot = helpers.MockBot()
+        self.bot.redis_session = await fakeredis.aioredis.create_redis_pool()
+
+        # Okay, so this is necessary so that we can create a clean new
+        # class for every test method, and we want that because it will
+        # ensure we get a fresh loop, which is necessary for test_increment_lock
+        # to be able to pass.
+        class DummyCog:
+            """A dummy cog, for dummies."""
+
+            redis = RedisCache()
+
+            def __init__(self, bot: helpers.MockBot):
+                self.bot = bot
+
+        self.cog = DummyCog(self.bot)
+
+        await self.cog.redis.clear()
+
+    def test_class_attribute_namespace(self):
+        """Test that RedisDict creates a namespace automatically for class attributes."""
+        self.assertEqual(self.cog.redis._namespace, "DummyCog.redis")
+
+    async def test_class_attribute_required(self):
+        """Test that errors are raised when not assigned as a class attribute."""
+        bad_cache = RedisCache()
+        self.assertIs(bad_cache._namespace, None)
+
+        with self.assertRaises(RuntimeError):
+            await bad_cache.set("test", "me_up_deadman")
+
+    async def test_set_get_item(self):
+        """Test that users can set and get items from the RedisDict."""
+        test_cases = (
+            ('favorite_fruit', 'melon'),
+            ('favorite_number', 86),
+            ('favorite_fraction', 86.54),
+            ('favorite_boolean', False),
+            ('other_boolean', True),
+        )
+
+        # Test that we can get and set different types.
+        for test in test_cases:
+            await self.cog.redis.set(*test)
+            self.assertEqual(await self.cog.redis.get(test[0]), test[1])
+
+        # Test that .get allows a default value
+        self.assertEqual(await self.cog.redis.get('favorite_nothing', "bearclaw"), "bearclaw")
+
+    async def test_set_item_type(self):
+        """Test that .set rejects keys and values that are not permitted."""
+        fruits = ["lemon", "melon", "apple"]
+
+        with self.assertRaises(TypeError):
+            await self.cog.redis.set(fruits, "nice")
+
+        with self.assertRaises(TypeError):
+            await self.cog.redis.set(4.23, "nice")
+
+    async def test_delete_item(self):
+        """Test that .delete allows us to delete stuff from the RedisCache."""
+        # Add an item and verify that it gets added
+        await self.cog.redis.set("internet", "firetruck")
+        self.assertEqual(await self.cog.redis.get("internet"), "firetruck")
+
+        # Delete that item and verify that it gets deleted
+        await self.cog.redis.delete("internet")
+        self.assertIs(await self.cog.redis.get("internet"), None)
+
+    async def test_contains(self):
+        """Test that we can check membership with .contains."""
+        await self.cog.redis.set('favorite_country', "Burkina Faso")
+
+        self.assertIs(await self.cog.redis.contains('favorite_country'), True)
+        self.assertIs(await self.cog.redis.contains('favorite_dentist'), False)
+
+    async def test_items(self):
+        """Test that the RedisDict can be iterated."""
+        # Set up our test cases in the Redis cache
+        test_cases = [
+            ('favorite_turtle', 'Donatello'),
+            ('second_favorite_turtle', 'Leonardo'),
+            ('third_favorite_turtle', 'Raphael'),
+        ]
+        for key, value in test_cases:
+            await self.cog.redis.set(key, value)
+
+        # Consume the AsyncIterator into a regular list, easier to compare that way.
+        redis_items = [item for item in await self.cog.redis.items()]
+
+        # These sequences are probably in the same order now, but probably
+        # isn't good enough for tests. Let's not rely on .hgetall always
+        # returning things in sequence, and just sort both lists to be safe.
+        redis_items = sorted(redis_items)
+        test_cases = sorted(test_cases)
+
+        # If these are equal now, everything works fine.
+        self.assertSequenceEqual(test_cases, redis_items)
+
+    async def test_length(self):
+        """Test that we can get the correct .length from the RedisDict."""
+        await self.cog.redis.set('one', 1)
+        await self.cog.redis.set('two', 2)
+        await self.cog.redis.set('three', 3)
+        self.assertEqual(await self.cog.redis.length(), 3)
+
+        await self.cog.redis.set('four', 4)
+        self.assertEqual(await self.cog.redis.length(), 4)
+
+    async def test_to_dict(self):
+        """Test that the .to_dict method returns a workable dictionary copy."""
+        copy = await self.cog.redis.to_dict()
+        local_copy = {key: value for key, value in await self.cog.redis.items()}
+        self.assertIs(type(copy), dict)
+        self.assertDictEqual(copy, local_copy)
+
+    async def test_clear(self):
+        """Test that the .clear method removes the entire hash."""
+        await self.cog.redis.set('teddy', 'with me')
+        await self.cog.redis.set('in my dreams', 'you have a weird hat')
+        self.assertEqual(await self.cog.redis.length(), 2)
+
+        await self.cog.redis.clear()
+        self.assertEqual(await self.cog.redis.length(), 0)
+
+    async def test_pop(self):
+        """Test that we can .pop an item from the RedisDict."""
+        await self.cog.redis.set('john', 'was afraid')
+
+        self.assertEqual(await self.cog.redis.pop('john'), 'was afraid')
+        self.assertEqual(await self.cog.redis.pop('pete', 'breakneck'), 'breakneck')
+        self.assertEqual(await self.cog.redis.length(), 0)
+
+    async def test_update(self):
+        """Test that we can .update the RedisDict with multiple items."""
+        await self.cog.redis.set("reckfried", "lona")
+        await self.cog.redis.set("bel air", "prince")
+        await self.cog.redis.update({
+            "reckfried": "jona",
+            "mega": "hungry, though",
+        })
+
+        result = {
+            "reckfried": "jona",
+            "bel air": "prince",
+            "mega": "hungry, though",
+        }
+        self.assertDictEqual(await self.cog.redis.to_dict(), result)
+
+    def test_typestring_conversion(self):
+        """Test the typestring-related helper functions."""
+        conversion_tests = (
+            (12, "i|12"),
+            (12.4, "f|12.4"),
+            ("cowabunga", "s|cowabunga"),
+        )
+
+        # Test conversion to typestring
+        for _input, expected in conversion_tests:
+            self.assertEqual(self.cog.redis._value_to_typestring(_input), expected)
+
+        # Test conversion from typestrings
+        for _input, expected in conversion_tests:
+            self.assertEqual(self.cog.redis._value_from_typestring(expected), _input)
+
+        # Test that exceptions are raised on invalid input
+        with self.assertRaises(TypeError):
+            self.cog.redis._value_to_typestring(["internet"])
+            self.cog.redis._value_from_typestring("o|firedog")
+
+    async def test_increment_decrement(self):
+        """Test .increment and .decrement methods."""
+        await self.cog.redis.set("entropic", 5)
+        await self.cog.redis.set("disentropic", 12.5)
+
+        # Test default increment
+        await self.cog.redis.increment("entropic")
+        self.assertEqual(await self.cog.redis.get("entropic"), 6)
+
+        # Test default decrement
+        await self.cog.redis.decrement("entropic")
+        self.assertEqual(await self.cog.redis.get("entropic"), 5)
+
+        # Test float increment with float
+        await self.cog.redis.increment("disentropic", 2.0)
+        self.assertEqual(await self.cog.redis.get("disentropic"), 14.5)
+
+        # Test float increment with int
+        await self.cog.redis.increment("disentropic", 2)
+        self.assertEqual(await self.cog.redis.get("disentropic"), 16.5)
+
+        # Test negative increments, because why not.
+        await self.cog.redis.increment("entropic", -5)
+        self.assertEqual(await self.cog.redis.get("entropic"), 0)
+
+        # Negative decrements? Sure.
+        await self.cog.redis.decrement("entropic", -5)
+        self.assertEqual(await self.cog.redis.get("entropic"), 5)
+
+        # What about if we use a negative float to decrement an int?
+        # This should convert the type into a float.
+        await self.cog.redis.decrement("entropic", -2.5)
+        self.assertEqual(await self.cog.redis.get("entropic"), 7.5)
+
+        # Let's test that they raise the right errors
+        with self.assertRaises(KeyError):
+            await self.cog.redis.increment("doesn't_exist!")
+
+        await self.cog.redis.set("stringthing", "stringthing")
+        with self.assertRaises(TypeError):
+            await self.cog.redis.increment("stringthing")
+
+    async def test_increment_lock(self):
+        """Test that we can't produce a race condition in .increment."""
+        await self.cog.redis.set("test_key", 0)
+        tasks = []
+
+        # Increment this a lot in different tasks
+        for _ in range(100):
+            task = asyncio.create_task(
+                self.cog.redis.increment("test_key", 1)
+            )
+            tasks.append(task)
+        await asyncio.gather(*tasks)
+
+        # Confirm that the value has been incremented the exact right number of times.
+        value = await self.cog.redis.get("test_key")
+        self.assertEqual(value, 100)
+
+    async def test_exceptions_raised(self):
+        """Testing that the various RuntimeErrors are reachable."""
+        class MyCog:
+            cache = RedisCache()
+
+            def __init__(self):
+                self.other_cache = RedisCache()
+
+        cog = MyCog()
+
+        # Raises "No Bot instance"
+        with self.assertRaises(NoBotInstanceError):
+            await cog.cache.get("john")
+
+        # Raises "RedisCache has no namespace"
+        with self.assertRaises(NoNamespaceError):
+            await cog.other_cache.get("was")
+
+        # Raises "You must access the RedisCache instance through the cog instance"
+        with self.assertRaises(NoParentInstanceError):
+            await MyCog.cache.get("afraid")
diff --git a/tests/helpers.py b/tests/helpers.py
index 2b79a6c2a..facc4e1af 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -4,12 +4,15 @@ import collections
 import itertools
 import logging
 import unittest.mock
-from typing import Iterable, Optional
+from asyncio import AbstractEventLoop
+from typing import Callable, Iterable, Optional
 
 import discord
+from aiohttp import ClientSession
 from discord.ext.commands import Context
 
 from bot.api import APIClient
+from bot.async_stats import AsyncStatsClient
 from bot.bot import Bot
 
 
@@ -23,6 +26,24 @@ for logger in logging.Logger.manager.loggerDict.values():
     logger.setLevel(logging.CRITICAL)
 
 
+def autospec(target, *attributes: str, **kwargs) -> Callable:
+    """Patch multiple `attributes` of a `target` with autospecced mocks and `spec_set` as True."""
+    # Caller's kwargs should take priority and overwrite the defaults.
+    kwargs = {'spec_set': True, 'autospec': True, **kwargs}
+
+    # Import the target if it's a string.
+    # This is to support both object and string targets like patch.multiple.
+    if type(target) is str:
+        target = unittest.mock._importer(target)
+
+    def decorator(func):
+        for attribute in attributes:
+            patcher = unittest.mock.patch.object(target, attribute, **kwargs)
+            func = patcher(func)
+        return func
+    return decorator
+
+
 class HashableMixin(discord.mixins.EqualityComparable):
     """
     Mixin that provides similar hashing and equality functionality as discord.py's `Hashable` mixin.
@@ -205,6 +226,10 @@ class MockRole(CustomMockMixin, unittest.mock.Mock, ColourMixin, HashableMixin):
         """Simplified position-based comparisons similar to those of `discord.Role`."""
         return self.position < other.position
 
+    def __ge__(self, other):
+        """Simplified position-based comparisons similar to those of `discord.Role`."""
+        return self.position >= other.position
+
 
 # Create a Member instance to get a realistic Mock of `discord.Member`
 member_data = {'user': 'lemon', 'roles': [1]}
@@ -264,10 +289,16 @@ class MockAPIClient(CustomMockMixin, unittest.mock.MagicMock):
     spec_set = APIClient
 
 
-# Create a Bot instance to get a realistic MagicMock of `discord.ext.commands.Bot`
-bot_instance = Bot(command_prefix=unittest.mock.MagicMock())
-bot_instance.http_session = None
-bot_instance.api_client = None
+def _get_mock_loop() -> unittest.mock.Mock:
+    """Return a mocked asyncio.AbstractEventLoop."""
+    loop = unittest.mock.create_autospec(spec=AbstractEventLoop, spec_set=True)
+
+    # Since calling `create_task` on our MockBot does not actually schedule the coroutine object
+    # as a task in the asyncio loop, this `side_effect` calls `close()` on the coroutine object
+    # to prevent "has not been awaited"-warnings.
+    loop.create_task.side_effect = lambda coroutine: coroutine.close()
+
+    return loop
 
 
 class MockBot(CustomMockMixin, unittest.mock.MagicMock):
@@ -277,17 +308,16 @@ class MockBot(CustomMockMixin, unittest.mock.MagicMock):
     Instances of this class will follow the specifications of `discord.ext.commands.Bot` instances.
     For more information, see the `MockGuild` docstring.
     """
-    spec_set = bot_instance
-    additional_spec_asyncs = ("wait_for",)
+    spec_set = Bot(command_prefix=unittest.mock.MagicMock(), loop=_get_mock_loop())
+    additional_spec_asyncs = ("wait_for", "redis_ready")
 
     def __init__(self, **kwargs) -> None:
         super().__init__(**kwargs)
-        self.api_client = MockAPIClient()
 
-        # Since calling `create_task` on our MockBot does not actually schedule the coroutine object
-        # as a task in the asyncio loop, this `side_effect` calls `close()` on the coroutine object
-        # to prevent "has not been awaited"-warnings.
-        self.loop.create_task.side_effect = lambda coroutine: coroutine.close()
+        self.loop = _get_mock_loop()
+        self.api_client = MockAPIClient(loop=self.loop)
+        self.http_session = unittest.mock.create_autospec(spec=ClientSession, spec_set=True)
+        self.stats = unittest.mock.create_autospec(spec=AsyncStatsClient, spec_set=True)
 
 
 # Create a TextChannel instance to get a realistic MagicMock of `discord.TextChannel`