Merge remote-tracking branch 'origin/master' into bug/backend/b754/scheduler-suppresses-errors

20 files changed, 1839 insertions, 451 deletions

diff --git a/tests/base.py b/tests/base.py
index 029a249ed..88693f382 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -1,6 +1,12 @@
 import logging
 import unittest
 from contextlib import contextmanager
+from typing import Dict
+
+import discord
+from discord.ext import commands
+
+from tests import helpers
 
 
 class _CaptureLogHandler(logging.Handler):
@@ -65,3 +71,31 @@ class LoggingTestCase(unittest.TestCase):
             standard_message = self._truncateMessage(base_message, record_message)
             msg = self._formatMessage(msg, standard_message)
             self.fail(msg)
+
+
+class CommandTestCase(unittest.TestCase):
+    """TestCase with additional assertions that are useful for testing Discord commands."""
+
+    @helpers.async_test
+    async def assertHasPermissionsCheck(
+        self,
+        cmd: commands.Command,
+        permissions: Dict[str, bool],
+    ) -> None:
+        """
+        Test that `cmd` raises a `MissingPermissions` exception if author lacks `permissions`.
+
+        Every permission in `permissions` is expected to be reported as missing. In other words, do
+        not include permissions which should not raise an exception along with those which should.
+        """
+        # Invert permission values because it's more intuitive to pass to this assertion the same
+        # permissions as those given to the check decorator.
+        permissions = {k: not v for k, v in permissions.items()}
+
+        ctx = helpers.MockContext()
+        ctx.channel.permissions_for.return_value = discord.Permissions(**permissions)
+
+        with self.assertRaises(commands.MissingPermissions) as cm:
+            await cmd.can_run(ctx)
+
+        self.assertCountEqual(permissions.keys(), cm.exception.missing_perms)
diff --git a/tests/bot/cogs/sync/test_base.py b/tests/bot/cogs/sync/test_base.py
new file mode 100644
index 000000000..e6a6f9688
--- /dev/null
+++ b/tests/bot/cogs/sync/test_base.py
@@ -0,0 +1,412 @@
+import unittest
+from unittest import mock
+
+import discord
+
+from bot import constants
+from bot.api import ResponseCodeError
+from bot.cogs.sync.syncers import Syncer, _Diff
+from tests import helpers
+
+
+class TestSyncer(Syncer):
+    """Syncer subclass with mocks for abstract methods for testing purposes."""
+
+    name = "test"
+    _get_diff = helpers.AsyncMock()
+    _sync = helpers.AsyncMock()
+
+
+class SyncerBaseTests(unittest.TestCase):
+    """Tests for the syncer base class."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+
+    def test_instantiation_fails_without_abstract_methods(self):
+        """The class must have abstract methods implemented."""
+        with self.assertRaisesRegex(TypeError, "Can't instantiate abstract class"):
+            Syncer(self.bot)
+
+
+class SyncerSendPromptTests(unittest.TestCase):
+    """Tests for sending the sync confirmation prompt."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+        self.syncer = TestSyncer(self.bot)
+
+    def mock_get_channel(self):
+        """Fixture to return a mock channel and message for when `get_channel` is used."""
+        self.bot.reset_mock()
+
+        mock_channel = helpers.MockTextChannel()
+        mock_message = helpers.MockMessage()
+
+        mock_channel.send.return_value = mock_message
+        self.bot.get_channel.return_value = mock_channel
+
+        return mock_channel, mock_message
+
+    def mock_fetch_channel(self):
+        """Fixture to return a mock channel and message for when `fetch_channel` is used."""
+        self.bot.reset_mock()
+
+        mock_channel = helpers.MockTextChannel()
+        mock_message = helpers.MockMessage()
+
+        self.bot.get_channel.return_value = None
+        mock_channel.send.return_value = mock_message
+        self.bot.fetch_channel.return_value = mock_channel
+
+        return mock_channel, mock_message
+
+    @helpers.async_test
+    async def test_send_prompt_edits_and_returns_message(self):
+        """The given message should be edited to display the prompt and then should be returned."""
+        msg = helpers.MockMessage()
+        ret_val = await self.syncer._send_prompt(msg)
+
+        msg.edit.assert_called_once()
+        self.assertIn("content", msg.edit.call_args[1])
+        self.assertEqual(ret_val, msg)
+
+    @helpers.async_test
+    async def test_send_prompt_gets_dev_core_channel(self):
+        """The dev-core channel should be retrieved if an extant message isn't given."""
+        subtests = (
+            (self.bot.get_channel, self.mock_get_channel),
+            (self.bot.fetch_channel, self.mock_fetch_channel),
+        )
+
+        for method, mock_ in subtests:
+            with self.subTest(method=method, msg=mock_.__name__):
+                mock_()
+                await self.syncer._send_prompt()
+
+                method.assert_called_once_with(constants.Channels.devcore)
+
+    @helpers.async_test
+    async def test_send_prompt_returns_None_if_channel_fetch_fails(self):
+        """None should be returned if there's an HTTPException when fetching the channel."""
+        self.bot.get_channel.return_value = None
+        self.bot.fetch_channel.side_effect = discord.HTTPException(mock.MagicMock(), "test error!")
+
+        ret_val = await self.syncer._send_prompt()
+
+        self.assertIsNone(ret_val)
+
+    @helpers.async_test
+    async def test_send_prompt_sends_and_returns_new_message_if_not_given(self):
+        """A new message mentioning core devs should be sent and returned if message isn't given."""
+        for mock_ in (self.mock_get_channel, self.mock_fetch_channel):
+            with self.subTest(msg=mock_.__name__):
+                mock_channel, mock_message = mock_()
+                ret_val = await self.syncer._send_prompt()
+
+                mock_channel.send.assert_called_once()
+                self.assertIn(self.syncer._CORE_DEV_MENTION, mock_channel.send.call_args[0][0])
+                self.assertEqual(ret_val, mock_message)
+
+    @helpers.async_test
+    async def test_send_prompt_adds_reactions(self):
+        """The message should have reactions for confirmation added."""
+        extant_message = helpers.MockMessage()
+        subtests = (
+            (extant_message, lambda: (None, extant_message)),
+            (None, self.mock_get_channel),
+            (None, self.mock_fetch_channel),
+        )
+
+        for message_arg, mock_ in subtests:
+            subtest_msg = "Extant message" if mock_.__name__ == "<lambda>" else mock_.__name__
+
+            with self.subTest(msg=subtest_msg):
+                _, mock_message = mock_()
+                await self.syncer._send_prompt(message_arg)
+
+                calls = [mock.call(emoji) for emoji in self.syncer._REACTION_EMOJIS]
+                mock_message.add_reaction.assert_has_calls(calls)
+
+
+class SyncerConfirmationTests(unittest.TestCase):
+    """Tests for waiting for a sync confirmation reaction on the prompt."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+        self.syncer = TestSyncer(self.bot)
+        self.core_dev_role = helpers.MockRole(id=constants.Roles.core_developer)
+
+    @staticmethod
+    def get_message_reaction(emoji):
+        """Fixture to return a mock message an reaction from the given `emoji`."""
+        message = helpers.MockMessage()
+        reaction = helpers.MockReaction(emoji=emoji, message=message)
+
+        return message, reaction
+
+    def test_reaction_check_for_valid_emoji_and_authors(self):
+        """Should return True if authors are identical or are a bot and a core dev, respectively."""
+        user_subtests = (
+            (
+                helpers.MockMember(id=77),
+                helpers.MockMember(id=77),
+                "identical users",
+            ),
+            (
+                helpers.MockMember(id=77, bot=True),
+                helpers.MockMember(id=43, roles=[self.core_dev_role]),
+                "bot author and core-dev reactor",
+            ),
+        )
+
+        for emoji in self.syncer._REACTION_EMOJIS:
+            for author, user, msg in user_subtests:
+                with self.subTest(author=author, user=user, emoji=emoji, msg=msg):
+                    message, reaction = self.get_message_reaction(emoji)
+                    ret_val = self.syncer._reaction_check(author, message, reaction, user)
+
+                    self.assertTrue(ret_val)
+
+    def test_reaction_check_for_invalid_reactions(self):
+        """Should return False for invalid reaction events."""
+        valid_emoji = self.syncer._REACTION_EMOJIS[0]
+        subtests = (
+            (
+                helpers.MockMember(id=77),
+                *self.get_message_reaction(valid_emoji),
+                helpers.MockMember(id=43, roles=[self.core_dev_role]),
+                "users are not identical",
+            ),
+            (
+                helpers.MockMember(id=77, bot=True),
+                *self.get_message_reaction(valid_emoji),
+                helpers.MockMember(id=43),
+                "reactor lacks the core-dev role",
+            ),
+            (
+                helpers.MockMember(id=77, bot=True, roles=[self.core_dev_role]),
+                *self.get_message_reaction(valid_emoji),
+                helpers.MockMember(id=77, bot=True, roles=[self.core_dev_role]),
+                "reactor is a bot",
+            ),
+            (
+                helpers.MockMember(id=77),
+                helpers.MockMessage(id=95),
+                helpers.MockReaction(emoji=valid_emoji, message=helpers.MockMessage(id=26)),
+                helpers.MockMember(id=77),
+                "messages are not identical",
+            ),
+            (
+                helpers.MockMember(id=77),
+                *self.get_message_reaction("InVaLiD"),
+                helpers.MockMember(id=77),
+                "emoji is invalid",
+            ),
+        )
+
+        for *args, msg in subtests:
+            kwargs = dict(zip(("author", "message", "reaction", "user"), args))
+            with self.subTest(**kwargs, msg=msg):
+                ret_val = self.syncer._reaction_check(*args)
+                self.assertFalse(ret_val)
+
+    @helpers.async_test
+    async def test_wait_for_confirmation(self):
+        """The message should always be edited and only return True if the emoji is a check mark."""
+        subtests = (
+            (constants.Emojis.check_mark, True, None),
+            ("InVaLiD", False, None),
+            (None, False, TimeoutError),
+        )
+
+        for emoji, ret_val, side_effect in subtests:
+            for bot in (True, False):
+                with self.subTest(emoji=emoji, ret_val=ret_val, side_effect=side_effect, bot=bot):
+                    # Set up mocks
+                    message = helpers.MockMessage()
+                    member = helpers.MockMember(bot=bot)
+
+                    self.bot.wait_for.reset_mock()
+                    self.bot.wait_for.return_value = (helpers.MockReaction(emoji=emoji), None)
+                    self.bot.wait_for.side_effect = side_effect
+
+                    # Call the function
+                    actual_return = await self.syncer._wait_for_confirmation(member, message)
+
+                    # Perform assertions
+                    self.bot.wait_for.assert_called_once()
+                    self.assertIn("reaction_add", self.bot.wait_for.call_args[0])
+
+                    message.edit.assert_called_once()
+                    kwargs = message.edit.call_args[1]
+                    self.assertIn("content", kwargs)
+
+                    # Core devs should only be mentioned if the author is a bot.
+                    if bot:
+                        self.assertIn(self.syncer._CORE_DEV_MENTION, kwargs["content"])
+                    else:
+                        self.assertNotIn(self.syncer._CORE_DEV_MENTION, kwargs["content"])
+
+                    self.assertIs(actual_return, ret_val)
+
+
+class SyncerSyncTests(unittest.TestCase):
+    """Tests for main function orchestrating the sync."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot(user=helpers.MockMember(bot=True))
+        self.syncer = TestSyncer(self.bot)
+
+    @helpers.async_test
+    async def test_sync_respects_confirmation_result(self):
+        """The sync should abort if confirmation fails and continue if confirmed."""
+        mock_message = helpers.MockMessage()
+        subtests = (
+            (True, mock_message),
+            (False, None),
+        )
+
+        for confirmed, message in subtests:
+            with self.subTest(confirmed=confirmed):
+                self.syncer._sync.reset_mock()
+                self.syncer._get_diff.reset_mock()
+
+                diff = _Diff({1, 2, 3}, {4, 5}, None)
+                self.syncer._get_diff.return_value = diff
+                self.syncer._get_confirmation_result = helpers.AsyncMock(
+                    return_value=(confirmed, message)
+                )
+
+                guild = helpers.MockGuild()
+                await self.syncer.sync(guild)
+
+                self.syncer._get_diff.assert_called_once_with(guild)
+                self.syncer._get_confirmation_result.assert_called_once()
+
+                if confirmed:
+                    self.syncer._sync.assert_called_once_with(diff)
+                else:
+                    self.syncer._sync.assert_not_called()
+
+    @helpers.async_test
+    async def test_sync_diff_size(self):
+        """The diff size should be correctly calculated."""
+        subtests = (
+            (6, _Diff({1, 2}, {3, 4}, {5, 6})),
+            (5, _Diff({1, 2, 3}, None, {4, 5})),
+            (0, _Diff(None, None, None)),
+            (0, _Diff(set(), set(), set())),
+        )
+
+        for size, diff in subtests:
+            with self.subTest(size=size, diff=diff):
+                self.syncer._get_diff.reset_mock()
+                self.syncer._get_diff.return_value = diff
+                self.syncer._get_confirmation_result = helpers.AsyncMock(return_value=(False, None))
+
+                guild = helpers.MockGuild()
+                await self.syncer.sync(guild)
+
+                self.syncer._get_diff.assert_called_once_with(guild)
+                self.syncer._get_confirmation_result.assert_called_once()
+                self.assertEqual(self.syncer._get_confirmation_result.call_args[0][0], size)
+
+    @helpers.async_test
+    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):
+                self.syncer._sync.side_effect = side_effect
+                self.syncer._get_confirmation_result = helpers.AsyncMock(
+                    return_value=(True, message)
+                )
+
+                guild = helpers.MockGuild()
+                await self.syncer.sync(guild)
+
+                if should_edit:
+                    message.edit.assert_called_once()
+                    self.assertIn("content", message.edit.call_args[1])
+
+    @helpers.async_test
+    async def test_sync_confirmation_context_redirect(self):
+        """If ctx is given, a new message should be sent and author should be ctx's author."""
+        mock_member = helpers.MockMember()
+        subtests = (
+            (None, self.bot.user, None),
+            (helpers.MockContext(author=mock_member), mock_member, helpers.MockMessage()),
+        )
+
+        for ctx, author, message in subtests:
+            with self.subTest(ctx=ctx, author=author, message=message):
+                if ctx is not None:
+                    ctx.send.return_value = message
+
+                self.syncer._get_confirmation_result = helpers.AsyncMock(return_value=(False, None))
+
+                guild = helpers.MockGuild()
+                await self.syncer.sync(guild, ctx)
+
+                if ctx is not None:
+                    ctx.send.assert_called_once()
+
+                self.syncer._get_confirmation_result.assert_called_once()
+                self.assertEqual(self.syncer._get_confirmation_result.call_args[0][1], author)
+                self.assertEqual(self.syncer._get_confirmation_result.call_args[0][2], message)
+
+    @mock.patch.object(constants.Sync, "max_diff", new=3)
+    @helpers.async_test
+    async def test_confirmation_result_small_diff(self):
+        """Should always return True and the given message if the diff size is too small."""
+        author = helpers.MockMember()
+        expected_message = helpers.MockMessage()
+
+        for size in (3, 2):
+            with self.subTest(size=size):
+                self.syncer._send_prompt = helpers.AsyncMock()
+                self.syncer._wait_for_confirmation = helpers.AsyncMock()
+
+                coro = self.syncer._get_confirmation_result(size, author, expected_message)
+                result, actual_message = await coro
+
+                self.assertTrue(result)
+                self.assertEqual(actual_message, expected_message)
+                self.syncer._send_prompt.assert_not_called()
+                self.syncer._wait_for_confirmation.assert_not_called()
+
+    @mock.patch.object(constants.Sync, "max_diff", new=3)
+    @helpers.async_test
+    async def test_confirmation_result_large_diff(self):
+        """Should return True if confirmed and False if _send_prompt fails or aborted."""
+        author = helpers.MockMember()
+        mock_message = helpers.MockMessage()
+
+        subtests = (
+            (True, mock_message, True, "confirmed"),
+            (False, None, False, "_send_prompt failed"),
+            (False, mock_message, False, "aborted"),
+        )
+
+        for expected_result, expected_message, confirmed, msg in subtests:
+            with self.subTest(msg=msg):
+                self.syncer._send_prompt = helpers.AsyncMock(return_value=expected_message)
+                self.syncer._wait_for_confirmation = helpers.AsyncMock(return_value=confirmed)
+
+                coro = self.syncer._get_confirmation_result(4, author)
+                actual_result, actual_message = await coro
+
+                self.syncer._send_prompt.assert_called_once_with(None)  # message defaults to None
+                self.assertIs(actual_result, expected_result)
+                self.assertEqual(actual_message, expected_message)
+
+                if expected_message:
+                    self.syncer._wait_for_confirmation.assert_called_once_with(
+                        author, expected_message
+                    )
diff --git a/tests/bot/cogs/sync/test_cog.py b/tests/bot/cogs/sync/test_cog.py
new file mode 100644
index 000000000..98c9afc0d
--- /dev/null
+++ b/tests/bot/cogs/sync/test_cog.py
@@ -0,0 +1,395 @@
+import unittest
+from unittest import mock
+
+import discord
+
+from bot import constants
+from bot.api import ResponseCodeError
+from bot.cogs import sync
+from bot.cogs.sync.syncers import Syncer
+from tests import helpers
+from tests.base import CommandTestCase
+
+
+class MockSyncer(helpers.CustomMockMixin, mock.MagicMock):
+    """
+    A MagicMock subclass to mock Syncer objects.
+
+    Instances of this class will follow the specifications of `bot.cogs.sync.syncers.Syncer`
+    instances. For more information, see the `MockGuild` docstring.
+    """
+
+    def __init__(self, **kwargs) -> None:
+        super().__init__(spec_set=Syncer, **kwargs)
+
+
+class SyncExtensionTests(unittest.TestCase):
+    """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.TestCase):
+    """Base class for Sync cog tests. Sets up patches for syncers."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+
+        # These patch the type. When the type is called, a MockSyncer instanced is returned.
+        # MockSyncer is needed so that our custom AsyncMock is used.
+        # TODO: Use autospec instead in 3.8, which will automatically use AsyncMock when needed.
+        self.role_syncer_patcher = mock.patch(
+            "bot.cogs.sync.syncers.RoleSyncer",
+            new=mock.MagicMock(return_value=MockSyncer())
+        )
+        self.user_syncer_patcher = mock.patch(
+            "bot.cogs.sync.syncers.UserSyncer",
+            new=mock.MagicMock(return_value=MockSyncer())
+        )
+        self.RoleSyncer = self.role_syncer_patcher.start()
+        self.UserSyncer = self.user_syncer_patcher.start()
+
+        self.cog = sync.Sync(self.bot)
+
+    def tearDown(self):
+        self.role_syncer_patcher.stop()
+        self.user_syncer_patcher.stop()
+
+    @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, "sync_guild")
+    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.reset_mock()
+
+        mock_sync_guild_coro = mock.MagicMock()
+        sync_guild.return_value = mock_sync_guild_coro
+
+        sync.Sync(self.bot)
+
+        self.RoleSyncer.assert_called_once_with(self.bot)
+        self.UserSyncer.assert_called_once_with(self.bot)
+        sync_guild.assert_called_once_with()
+        self.bot.loop.create_task.assert_called_once_with(mock_sync_guild_coro)
+
+    @helpers.async_test
+    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.cog.role_syncer.reset_mock()
+                self.cog.user_syncer.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.cog.role_syncer.sync.assert_not_called()
+                    self.cog.user_syncer.sync.assert_not_called()
+                else:
+                    self.cog.role_syncer.sync.assert_called_once_with(guild)
+                    self.cog.user_syncer.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,
+        )
+
+    @helpers.async_test
+    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)
+
+    @helpers.async_test
+    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 = helpers.AsyncMock(spec_set=self.cog.patch_user)
+
+    @helpers.async_test
+    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)
+        await self.cog.on_guild_role_create(role)
+
+        self.bot.api_client.post.assert_called_once_with("bot/roles", json=role_data)
+
+    @helpers.async_test
+    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)
+        await self.cog.on_guild_role_delete(role)
+
+        self.bot.api_client.delete.assert_called_once_with("bot/roles/99")
+
+    @helpers.async_test
+    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)
+                    after_role = helpers.MockRole(**after_role_data)
+
+                    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()
+
+    @helpers.async_test
+    async def test_sync_cog_on_member_remove(self):
+        """Member should patched to set in_guild as False."""
+        self.assertTrue(self.cog.on_member_remove.__cog_listener__)
+
+        member = helpers.MockMember()
+        await self.cog.on_member_remove(member)
+
+        self.cog.patch_user.assert_called_once_with(
+            member.id,
+            updated_information={"in_guild": False}
+        )
+
+    @helpers.async_test
+    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)
+        after_member = helpers.MockMember(roles=before_roles[1:])
+
+        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, updated_information=data)
+
+    @helpers.async_test
+    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})
+                after_member = helpers.MockMember(**{attribute: new_value})
+
+                await self.cog.on_member_update(before_member, after_member)
+
+                self.cog.patch_user.assert_not_called()
+
+    @helpers.async_test
+    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",
+            "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),
+        )
+
+        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[0][0], after_user.id)
+                    self.assertIn("updated_information", call_args[1])
+
+                    updated_information = call_args[1]["updated_information"]
+                    self.assertIn(api_field, updated_information)
+                    self.assertEqual(updated_information[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)],
+        )
+
+        data = {
+            "avatar_hash": member.avatar,
+            "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
+
+    @helpers.async_test
+    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()
+
+    @helpers.async_test
+    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()
+
+
+class SyncCogCommandTests(SyncCogTestCase, CommandTestCase):
+    """Tests for the commands in the Sync cog."""
+
+    @helpers.async_test
+    async def test_sync_roles_command(self):
+        """sync() should be called on the RoleSyncer."""
+        ctx = helpers.MockContext()
+        await self.cog.sync_roles_command.callback(self.cog, ctx)
+
+        self.cog.role_syncer.sync.assert_called_once_with(ctx.guild, ctx)
+
+    @helpers.async_test
+    async def test_sync_users_command(self):
+        """sync() should be called on the UserSyncer."""
+        ctx = helpers.MockContext()
+        await self.cog.sync_users_command.callback(self.cog, ctx)
+
+        self.cog.user_syncer.sync.assert_called_once_with(ctx.guild, ctx)
+
+    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):
+                self.assertHasPermissionsCheck(cmd, {"administrator": True})
diff --git a/tests/bot/cogs/sync/test_roles.py b/tests/bot/cogs/sync/test_roles.py
index 27ae27639..14fb2577a 100644
--- a/tests/bot/cogs/sync/test_roles.py
+++ b/tests/bot/cogs/sync/test_roles.py
@@ -1,126 +1,165 @@
 import unittest
+from unittest import mock
 
-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)},
-            )
-        )
+import discord
+
+from bot.cogs.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.TestCase):
+    """Tests for determining differences between roles in the DB and roles in the Guild cache."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+        self.syncer = RoleSyncer(self.bot)
+
+    @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
+
+    @helpers.async_test
+    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 self.syncer._get_diff(guild)
+        expected_diff = (set(), set(), set())
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    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 self.syncer._get_diff(guild)
+        expected_diff = (set(), {_Role(**updated_role)}, set())
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    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 self.syncer._get_diff(guild)
+        expected_diff = ({_Role(**new_role)}, set(), set())
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    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 self.syncer._get_diff(guild)
+        expected_diff = (set(), set(), {_Role(**deleted_role)})
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    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 self.syncer._get_diff(guild)
+        expected_diff = ({_Role(**new)}, {_Role(**updated)}, {_Role(**deleted)})
+
+        self.assertEqual(actual_diff, expected_diff)
+
+
+class RoleSyncerSyncTests(unittest.TestCase):
+    """Tests for the API requests that sync roles."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+        self.syncer = RoleSyncer(self.bot)
+
+    @helpers.async_test
+    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 self.syncer._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()
+
+    @helpers.async_test
+    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 self.syncer._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()
+
+    @helpers.async_test
+    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 self.syncer._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/cogs/sync/test_users.py b/tests/bot/cogs/sync/test_users.py
index ccaf67490..421bf6bb6 100644
--- a/tests/bot/cogs/sync/test_users.py
+++ b/tests/bot/cogs/sync/test_users.py
@@ -1,84 +1,169 @@
 import unittest
+from unittest import mock
 
-from bot.cogs.sync.syncers import User, get_users_for_sync
+from bot.cogs.sync.syncers import UserSyncer, _Diff, _User
+from tests import helpers
 
 
 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):
+    """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("avatar_hash", None)
+    kwargs.setdefault("roles", (666,))
+    kwargs.setdefault("in_guild", True)
+
+    return kwargs
+
+
+class UserSyncerDiffTests(unittest.TestCase):
+    """Tests for determining differences between users in the DB and users in the Guild cache."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+        self.syncer = UserSyncer(self.bot)
+
+    @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()
+            member["avatar"] = member.pop("avatar_hash")
+            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
+
+    @helpers.async_test
+    async def test_empty_diff_for_no_users(self):
+        """When no users are given, an empty diff should be returned."""
+        guild = self.get_guild()
+
+        actual_diff = await self.syncer._get_diff(guild)
+        expected_diff = (set(), set(), None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    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 = [fake_user()]
+        guild = self.get_guild(fake_user())
+
+        actual_diff = await self.syncer._get_diff(guild)
+        expected_diff = (set(), set(), None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    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 = [fake_user(id=99, name="old"), fake_user()]
+        guild = self.get_guild(updated_user, fake_user())
+
+        actual_diff = await self.syncer._get_diff(guild)
+        expected_diff = (set(), {_User(**updated_user)}, None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    async def test_diff_for_new_users(self):
+        """Only new users should be added to the 'created' set of the diff."""
+        new_user = fake_user(id=99, name="new")
+
+        self.bot.api_client.get.return_value = [fake_user()]
+        guild = self.get_guild(fake_user(), new_user)
+
+        actual_diff = await self.syncer._get_diff(guild)
+        expected_diff = ({_User(**new_user)}, set(), None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    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`."""
-        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())
-        )
+        leaving_user = fake_user(id=63, in_guild=False)
+
+        self.bot.api_client.get.return_value = [fake_user(), fake_user(id=63)]
+        guild = self.get_guild(fake_user())
+
+        actual_diff = await self.syncer._get_diff(guild)
+        expected_diff = (set(), {_User(**leaving_user)}, None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    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")
+        leaving_user = fake_user(id=63, in_guild=False)
+
+        self.bot.api_client.get.return_value = [fake_user(), fake_user(id=55), fake_user(id=63)]
+        guild = self.get_guild(fake_user(), new_user, updated_user)
+
+        actual_diff = await self.syncer._get_diff(guild)
+        expected_diff = ({_User(**new_user)}, {_User(**updated_user), _User(**leaving_user)}, None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+    @helpers.async_test
+    async def test_empty_diff_for_db_users_not_in_guild(self):
+        """When the DB knows a user the guild doesn't, no difference is found."""
+        self.bot.api_client.get.return_value = [fake_user(), fake_user(id=63, in_guild=False)]
+        guild = self.get_guild(fake_user())
+
+        actual_diff = await self.syncer._get_diff(guild)
+        expected_diff = (set(), set(), None)
+
+        self.assertEqual(actual_diff, expected_diff)
+
+
+class UserSyncerSyncTests(unittest.TestCase):
+    """Tests for the API requests that sync users."""
+
+    def setUp(self):
+        self.bot = helpers.MockBot()
+        self.syncer = UserSyncer(self.bot)
+
+    @helpers.async_test
+    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)]
+
+        user_tuples = {_User(**user) for user in users}
+        diff = _Diff(user_tuples, set(), None)
+        await self.syncer._sync(diff)
+
+        calls = [mock.call("bot/users", json=user) for user in users]
+        self.bot.api_client.post.assert_has_calls(calls, any_order=True)
+        self.assertEqual(self.bot.api_client.post.call_count, len(users))
+
+        self.bot.api_client.put.assert_not_called()
+        self.bot.api_client.delete.assert_not_called()
+
+    @helpers.async_test
+    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)]
+
+        user_tuples = {_User(**user) for user in users}
+        diff = _Diff(set(), user_tuples, None)
+        await self.syncer._sync(diff)
+
+        calls = [mock.call(f"bot/users/{user['id']}", json=user) for user in users]
+        self.bot.api_client.put.assert_has_calls(calls, any_order=True)
+        self.assertEqual(self.bot.api_client.put.call_count, len(users))
+
+        self.bot.api_client.post.assert_not_called()
+        self.bot.api_client.delete.assert_not_called()
diff --git a/tests/bot/cogs/test_duck_pond.py b/tests/bot/cogs/test_duck_pond.py
index d07b2bce1..5b0a3b8c3 100644
--- a/tests/bot/cogs/test_duck_pond.py
+++ b/tests/bot/cogs/test_duck_pond.py
@@ -54,7 +54,7 @@ class DuckPondTests(base.LoggingTestCase):
 
         asyncio.run(self.cog.fetch_webhook())
 
-        self.bot.wait_until_ready.assert_called_once()
+        self.bot.wait_until_guild_available.assert_called_once()
         self.bot.fetch_webhook.assert_called_once_with(1)
         self.assertEqual(self.cog.webhook, "dummy webhook")
 
@@ -67,7 +67,7 @@ class DuckPondTests(base.LoggingTestCase):
         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.wait_until_guild_available.assert_called_once()
         self.bot.fetch_webhook.assert_called_once_with(1)
 
         self.assertEqual(len(log_watcher.records), 1)
diff --git a/tests/bot/cogs/test_information.py b/tests/bot/cogs/test_information.py
index 4496a2ae0..deae7ebad 100644
--- a/tests/bot/cogs/test_information.py
+++ b/tests/bot/cogs/test_information.py
@@ -125,10 +125,10 @@ class InformationCogTests(unittest.TestCase):
                 )
             ],
             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)),
+                *(helpers.MockMember(status=discord.Status.online) for _ in range(2)),
+                *(helpers.MockMember(status=discord.Status.idle) for _ in range(1)),
+                *(helpers.MockMember(status=discord.Status.dnd) for _ in range(4)),
+                *(helpers.MockMember(status=discord.Status.offline) for _ in range(3)),
             ],
             member_count=1_234,
             icon_url='a-lemon.jpg',
@@ -153,9 +153,9 @@ class InformationCogTests(unittest.TestCase):
                 **Counts**
                 Members: {self.ctx.guild.member_count:,}
                 Roles: {len(self.ctx.guild.roles)}
-                Text: 1
-                Voice: 1
-                Channel categories: 1
+                Category channels: 1
+                Text channels: 1
+                Voice channels: 1
 
                 **Members**
                 {constants.Emojis.status_online} 2
diff --git a/tests/bot/rules/__init__.py b/tests/bot/rules/__init__.py
index e69de29bb..36c986fe1 100644
--- a/tests/bot/rules/__init__.py
+++ b/tests/bot/rules/__init__.py
@@ -0,0 +1,76 @@
+import unittest
+from abc import ABCMeta, abstractmethod
+from typing import Callable, Dict, Iterable, List, NamedTuple, Tuple
+
+from tests.helpers import MockMessage
+
+
+class DisallowedCase(NamedTuple):
+    """Encapsulation for test cases expected to fail."""
+    recent_messages: List[MockMessage]
+    culprits: Iterable[str]
+    n_violations: int
+
+
+class RuleTest(unittest.TestCase, metaclass=ABCMeta):
+    """
+    Abstract class for antispam rule test cases.
+
+    Tests for specific rules should inherit from `RuleTest` and implement
+    `relevant_messages` and `get_report`. Each instance should also set the
+    `apply` and `config` attributes as necessary.
+
+    The execution of test cases can then be delegated to the `run_allowed`
+    and `run_disallowed` methods.
+    """
+
+    apply: Callable  # The tested rule's apply function
+    config: Dict[str, int]
+
+    async def run_allowed(self, cases: Tuple[List[MockMessage], ...]) -> None:
+        """Run all `cases` against `self.apply` expecting them to pass."""
+        for recent_messages in cases:
+            last_message = recent_messages[0]
+
+            with self.subTest(
+                last_message=last_message,
+                recent_messages=recent_messages,
+                config=self.config,
+            ):
+                self.assertIsNone(
+                    await self.apply(last_message, recent_messages, self.config)
+                )
+
+    async def run_disallowed(self, cases: Tuple[DisallowedCase, ...]) -> None:
+        """Run all `cases` against `self.apply` expecting them to fail."""
+        for case in cases:
+            recent_messages, culprits, n_violations = case
+            last_message = recent_messages[0]
+            relevant_messages = self.relevant_messages(case)
+            desired_output = (
+                self.get_report(case),
+                culprits,
+                relevant_messages,
+            )
+
+            with self.subTest(
+                last_message=last_message,
+                recent_messages=recent_messages,
+                relevant_messages=relevant_messages,
+                n_violations=n_violations,
+                config=self.config,
+            ):
+                self.assertTupleEqual(
+                    await self.apply(last_message, recent_messages, self.config),
+                    desired_output,
+                )
+
+    @abstractmethod
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        """Give expected relevant messages for `case`."""
+        raise NotImplementedError
+
+    @abstractmethod
+    def get_report(self, case: DisallowedCase) -> str:
+        """Give expected error report for `case`."""
+        raise NotImplementedError
diff --git a/tests/bot/rules/test_attachments.py b/tests/bot/rules/test_attachments.py
index d7187f315..e54b4b5b8 100644
--- a/tests/bot/rules/test_attachments.py
+++ b/tests/bot/rules/test_attachments.py
@@ -1,98 +1,71 @@
-import unittest
-from typing import List, NamedTuple, Tuple
+from typing import Iterable
 
 from bot.rules import attachments
+from tests.bot.rules import DisallowedCase, RuleTest
 from tests.helpers import MockMessage, async_test
 
 
-class Case(NamedTuple):
-    recent_messages: List[MockMessage]
-    culprit: Tuple[str]
-    total_attachments: int
-
-
-def msg(author: str, total_attachments: int) -> MockMessage:
+def make_msg(author: str, total_attachments: int) -> MockMessage:
     """Builds a message with `total_attachments` attachments."""
     return MockMessage(author=author, attachments=list(range(total_attachments)))
 
 
-class AttachmentRuleTests(unittest.TestCase):
+class AttachmentRuleTests(RuleTest):
     """Tests applying the `attachments` antispam rule."""
 
     def setUp(self):
-        self.config = {"max": 5}
+        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 = (
-            [msg("bob", 0), msg("bob", 0), msg("bob", 0)],
-            [msg("bob", 2), msg("bob", 2)],
-            [msg("bob", 2), msg("alice", 2), msg("bob", 2)],
+            [make_msg("bob", 0), make_msg("bob", 0), make_msg("bob", 0)],
+            [make_msg("bob", 2), make_msg("bob", 2)],
+            [make_msg("bob", 2), make_msg("alice", 2), make_msg("bob", 2)],
         )
 
-        for recent_messages in cases:
-            last_message = recent_messages[0]
-
-            with self.subTest(
-                last_message=last_message,
-                recent_messages=recent_messages,
-                config=self.config
-            ):
-                self.assertIsNone(
-                    await attachments.apply(last_message, recent_messages, self.config)
-                )
+        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 = (
-            Case(
-                [msg("bob", 4), msg("bob", 0), msg("bob", 6)],
+            DisallowedCase(
+                [make_msg("bob", 4), make_msg("bob", 0), make_msg("bob", 6)],
                 ("bob",),
-                10
+                10,
             ),
-            Case(
-                [msg("bob", 4), msg("alice", 6), msg("bob", 2)],
+            DisallowedCase(
+                [make_msg("bob", 4), make_msg("alice", 6), make_msg("bob", 2)],
                 ("bob",),
-                6
+                6,
             ),
-            Case(
-                [msg("alice", 6)],
+            DisallowedCase(
+                [make_msg("alice", 6)],
                 ("alice",),
-                6
+                6,
             ),
-            (
-                [msg("alice", 1) for _ in range(6)],
+            DisallowedCase(
+                [make_msg("alice", 1) for _ in range(6)],
                 ("alice",),
-                6
+                6,
             ),
         )
 
-        for recent_messages, culprit, total_attachments in cases:
-            last_message = recent_messages[0]
-            relevant_messages = tuple(
-                msg
-                for msg in recent_messages
-                if (
-                    msg.author == last_message.author
-                    and len(msg.attachments) > 0
-                )
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        last_message = case.recent_messages[0]
+        return tuple(
+            msg
+            for msg in case.recent_messages
+            if (
+                msg.author == last_message.author
+                and len(msg.attachments) > 0
             )
+        )
 
-            with self.subTest(
-                last_message=last_message,
-                recent_messages=recent_messages,
-                relevant_messages=relevant_messages,
-                total_attachments=total_attachments,
-                config=self.config
-            ):
-                desired_output = (
-                    f"sent {total_attachments} attachments in {self.config['max']}s",
-                    culprit,
-                    relevant_messages
-                )
-                self.assertTupleEqual(
-                    await attachments.apply(last_message, recent_messages, self.config),
-                    desired_output
-                )
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} attachments in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_burst.py b/tests/bot/rules/test_burst.py
new file mode 100644
index 000000000..72f0be0c7
--- /dev/null
+++ b/tests/bot/rules/test_burst.py
@@ -0,0 +1,56 @@
+from typing import Iterable
+
+from bot.rules import burst
+from tests.bot.rules import DisallowedCase, RuleTest
+from tests.helpers import MockMessage, async_test
+
+
+def make_msg(author: str) -> MockMessage:
+    """
+    Init a MockMessage instance with author set to `author`.
+
+    This serves as a shorthand / alias to keep the test cases visually clean.
+    """
+    return MockMessage(author=author)
+
+
+class BurstRuleTests(RuleTest):
+    """Tests the `burst` antispam rule."""
+
+    def setUp(self):
+        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 = (
+            [make_msg("bob"), make_msg("bob")],
+            [make_msg("bob"), make_msg("alice"), make_msg("bob")],
+        )
+
+        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 = (
+            DisallowedCase(
+                [make_msg("bob"), make_msg("bob"), make_msg("bob")],
+                ("bob",),
+                3,
+            ),
+            DisallowedCase(
+                [make_msg("bob"), make_msg("bob"), make_msg("alice"), make_msg("bob")],
+                ("bob",),
+                3,
+            ),
+        )
+
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        return tuple(msg for msg in case.recent_messages if msg.author in case.culprits)
+
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} messages in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_burst_shared.py b/tests/bot/rules/test_burst_shared.py
new file mode 100644
index 000000000..47367a5f8
--- /dev/null
+++ b/tests/bot/rules/test_burst_shared.py
@@ -0,0 +1,59 @@
+from typing import Iterable
+
+from bot.rules import burst_shared
+from tests.bot.rules import DisallowedCase, RuleTest
+from tests.helpers import MockMessage, async_test
+
+
+def make_msg(author: str) -> MockMessage:
+    """
+    Init a MockMessage instance with the passed arg.
+
+    This serves as a shorthand / alias to keep the test cases visually clean.
+    """
+    return MockMessage(author=author)
+
+
+class BurstSharedRuleTests(RuleTest):
+    """Tests the `burst_shared` antispam rule."""
+
+    def setUp(self):
+        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.
+
+        There really isn't more to test here than a single case.
+        """
+        cases = (
+            [make_msg("spongebob"), make_msg("patrick")],
+        )
+
+        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 = (
+            DisallowedCase(
+                [make_msg("bob"), make_msg("bob"), make_msg("bob")],
+                {"bob"},
+                3,
+            ),
+            DisallowedCase(
+                [make_msg("bob"), make_msg("bob"), make_msg("alice"), make_msg("bob")],
+                {"bob", "alice"},
+                4,
+            ),
+        )
+
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        return case.recent_messages
+
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} messages in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_chars.py b/tests/bot/rules/test_chars.py
new file mode 100644
index 000000000..7cc36f49e
--- /dev/null
+++ b/tests/bot/rules/test_chars.py
@@ -0,0 +1,66 @@
+from typing import Iterable
+
+from bot.rules import chars
+from tests.bot.rules import DisallowedCase, RuleTest
+from tests.helpers import MockMessage, async_test
+
+
+def make_msg(author: str, n_chars: int) -> MockMessage:
+    """Build a message with arbitrary content of `n_chars` length."""
+    return MockMessage(author=author, content="A" * n_chars)
+
+
+class CharsRuleTests(RuleTest):
+    """Tests the `chars` antispam rule."""
+
+    def setUp(self):
+        self.apply = chars.apply
+        self.config = {
+            "max": 20,  # Max allowed sum of chars per user
+            "interval": 10,
+        }
+
+    @async_test
+    async def test_allows_messages_within_limit(self):
+        """Cases with a total amount of chars within limit."""
+        cases = (
+            [make_msg("bob", 0)],
+            [make_msg("bob", 20)],
+            [make_msg("bob", 15), make_msg("alice", 15)],
+        )
+
+        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 = (
+            DisallowedCase(
+                [make_msg("bob", 21)],
+                ("bob",),
+                21,
+            ),
+            DisallowedCase(
+                [make_msg("bob", 15), make_msg("bob", 15)],
+                ("bob",),
+                30,
+            ),
+            DisallowedCase(
+                [make_msg("alice", 15), make_msg("bob", 20), make_msg("alice", 15)],
+                ("alice",),
+                30,
+            ),
+        )
+
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        last_message = case.recent_messages[0]
+        return tuple(
+            msg
+            for msg in case.recent_messages
+            if msg.author == last_message.author
+        )
+
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} characters in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_discord_emojis.py b/tests/bot/rules/test_discord_emojis.py
new file mode 100644
index 000000000..0239b0b00
--- /dev/null
+++ b/tests/bot/rules/test_discord_emojis.py
@@ -0,0 +1,54 @@
+from typing import Iterable
+
+from bot.rules import discord_emojis
+from tests.bot.rules import DisallowedCase, RuleTest
+from tests.helpers import MockMessage, async_test
+
+discord_emoji = "<:abcd:1234>"  # Discord emojis follow the format <:name:id>
+
+
+def make_msg(author: str, n_emojis: int) -> MockMessage:
+    """Build a MockMessage instance with content containing `n_emojis` arbitrary emojis."""
+    return MockMessage(author=author, content=discord_emoji * n_emojis)
+
+
+class DiscordEmojisRuleTests(RuleTest):
+    """Tests for the `discord_emojis` antispam rule."""
+
+    def setUp(self):
+        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 = (
+            [make_msg("bob", 2)],
+            [make_msg("alice", 1), make_msg("bob", 2), make_msg("alice", 1)],
+        )
+
+        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 = (
+            DisallowedCase(
+                [make_msg("bob", 3)],
+                ("bob",),
+                3,
+            ),
+            DisallowedCase(
+                [make_msg("alice", 2), make_msg("bob", 2), make_msg("alice", 2)],
+                ("alice",),
+                4,
+            ),
+        )
+
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        return tuple(msg for msg in case.recent_messages if msg.author in case.culprits)
+
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} emojis in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_duplicates.py b/tests/bot/rules/test_duplicates.py
new file mode 100644
index 000000000..59e0fb6ef
--- /dev/null
+++ b/tests/bot/rules/test_duplicates.py
@@ -0,0 +1,66 @@
+from typing import Iterable
+
+from bot.rules import duplicates
+from tests.bot.rules import DisallowedCase, RuleTest
+from tests.helpers import MockMessage, async_test
+
+
+def make_msg(author: str, content: str) -> MockMessage:
+    """Give a MockMessage instance with `author` and `content` attrs."""
+    return MockMessage(author=author, content=content)
+
+
+class DuplicatesRuleTests(RuleTest):
+    """Tests the `duplicates` antispam rule."""
+
+    def setUp(self):
+        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 = (
+            [make_msg("alice", "A"), make_msg("alice", "A")],
+            [make_msg("alice", "A"), make_msg("alice", "B"), make_msg("alice", "C")],  # Non-duplicate
+            [make_msg("alice", "A"), make_msg("bob", "A"), make_msg("alice", "A")],  # Different author
+        )
+
+        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 = (
+            DisallowedCase(
+                [make_msg("alice", "A"), make_msg("alice", "A"), make_msg("alice", "A")],
+                ("alice",),
+                3,
+            ),
+            DisallowedCase(
+                [make_msg("bob", "A"), make_msg("alice", "A"), make_msg("bob", "A"), make_msg("bob", "A")],
+                ("bob",),
+                3,  # 4 duplicate messages, but only 3 from bob
+            ),
+            DisallowedCase(
+                [make_msg("bob", "A"), make_msg("bob", "B"), make_msg("bob", "A"), make_msg("bob", "A")],
+                ("bob",),
+                3,  # 4 message from bob, but only 3 duplicates
+            ),
+        )
+
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        last_message = case.recent_messages[0]
+        return tuple(
+            msg
+            for msg in case.recent_messages
+            if (
+                msg.author == last_message.author
+                and msg.content == last_message.content
+            )
+        )
+
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} duplicated messages in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_links.py b/tests/bot/rules/test_links.py
index 02a5d5501..3c3f90e5f 100644
--- a/tests/bot/rules/test_links.py
+++ b/tests/bot/rules/test_links.py
@@ -1,26 +1,21 @@
-import unittest
-from typing import List, NamedTuple, Tuple
+from typing import Iterable
 
 from bot.rules import links
+from tests.bot.rules import DisallowedCase, RuleTest
 from tests.helpers import MockMessage, async_test
 
 
-class Case(NamedTuple):
-    recent_messages: List[MockMessage]
-    culprit: Tuple[str]
-    total_links: int
-
-
-def msg(author: str, total_links: int) -> MockMessage:
+def make_msg(author: str, total_links: int) -> MockMessage:
     """Makes a message with `total_links` links."""
     content = " ".join(["https://pydis.com"] * total_links)
     return MockMessage(author=author, content=content)
 
 
-class LinksTests(unittest.TestCase):
+class LinksTests(RuleTest):
     """Tests applying the `links` rule."""
 
     def setUp(self):
+        self.apply = links.apply
         self.config = {
             "max": 2,
             "interval": 10
@@ -30,68 +25,45 @@ class LinksTests(unittest.TestCase):
     async def test_links_within_limit(self):
         """Messages with an allowed amount of links."""
         cases = (
-            [msg("bob", 0)],
-            [msg("bob", 2)],
-            [msg("bob", 3)],  # Filter only applies if len(messages_with_links) > 1
-            [msg("bob", 1), msg("bob", 1)],
-            [msg("bob", 2), msg("alice", 2)]  # Only messages from latest author count
+            [make_msg("bob", 0)],
+            [make_msg("bob", 2)],
+            [make_msg("bob", 3)],  # Filter only applies if len(messages_with_links) > 1
+            [make_msg("bob", 1), make_msg("bob", 1)],
+            [make_msg("bob", 2), make_msg("alice", 2)]  # Only messages from latest author count
         )
 
-        for recent_messages in cases:
-            last_message = recent_messages[0]
-
-            with self.subTest(
-                last_message=last_message,
-                recent_messages=recent_messages,
-                config=self.config
-            ):
-                self.assertIsNone(
-                    await links.apply(last_message, recent_messages, self.config)
-                )
+        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 = (
-            Case(
-                [msg("bob", 1), msg("bob", 2)],
+            DisallowedCase(
+                [make_msg("bob", 1), make_msg("bob", 2)],
                 ("bob",),
                 3
             ),
-            Case(
-                [msg("alice", 1), msg("alice", 1), msg("alice", 1)],
+            DisallowedCase(
+                [make_msg("alice", 1), make_msg("alice", 1), make_msg("alice", 1)],
                 ("alice",),
                 3
             ),
-            Case(
-                [msg("alice", 2), msg("bob", 3), msg("alice", 1)],
+            DisallowedCase(
+                [make_msg("alice", 2), make_msg("bob", 3), make_msg("alice", 1)],
                 ("alice",),
                 3
             )
         )
 
-        for recent_messages, culprit, total_links in cases:
-            last_message = recent_messages[0]
-            relevant_messages = tuple(
-                msg
-                for msg in recent_messages
-                if msg.author == last_message.author
-            )
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        last_message = case.recent_messages[0]
+        return tuple(
+            msg
+            for msg in case.recent_messages
+            if msg.author == last_message.author
+        )
 
-            with self.subTest(
-                last_message=last_message,
-                recent_messages=recent_messages,
-                relevant_messages=relevant_messages,
-                culprit=culprit,
-                total_links=total_links,
-                config=self.config
-            ):
-                desired_output = (
-                    f"sent {total_links} links in {self.config['interval']}s",
-                    culprit,
-                    relevant_messages
-                )
-                self.assertTupleEqual(
-                    await links.apply(last_message, recent_messages, self.config),
-                    desired_output
-                )
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} links in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_mentions.py b/tests/bot/rules/test_mentions.py
index ad49ead32..ebcdabac6 100644
--- a/tests/bot/rules/test_mentions.py
+++ b/tests/bot/rules/test_mentions.py
@@ -1,95 +1,67 @@
-import unittest
-from typing import List, NamedTuple, Tuple
+from typing import Iterable
 
 from bot.rules import mentions
+from tests.bot.rules import DisallowedCase, RuleTest
 from tests.helpers import MockMessage, async_test
 
 
-class Case(NamedTuple):
-    recent_messages: List[MockMessage]
-    culprit: Tuple[str]
-    total_mentions: int
-
-
-def msg(author: str, total_mentions: int) -> MockMessage:
+def make_msg(author: str, total_mentions: int) -> MockMessage:
     """Makes a message with `total_mentions` mentions."""
     return MockMessage(author=author, mentions=list(range(total_mentions)))
 
 
-class TestMentions(unittest.TestCase):
+class TestMentions(RuleTest):
     """Tests applying the `mentions` antispam rule."""
 
     def setUp(self):
+        self.apply = mentions.apply
         self.config = {
             "max": 2,
-            "interval": 10
+            "interval": 10,
         }
 
     @async_test
     async def test_mentions_within_limit(self):
         """Messages with an allowed amount of mentions."""
         cases = (
-            [msg("bob", 0)],
-            [msg("bob", 2)],
-            [msg("bob", 1), msg("bob", 1)],
-            [msg("bob", 1), msg("alice", 2)]
+            [make_msg("bob", 0)],
+            [make_msg("bob", 2)],
+            [make_msg("bob", 1), make_msg("bob", 1)],
+            [make_msg("bob", 1), make_msg("alice", 2)],
         )
 
-        for recent_messages in cases:
-            last_message = recent_messages[0]
-
-            with self.subTest(
-                last_message=last_message,
-                recent_messages=recent_messages,
-                config=self.config
-            ):
-                self.assertIsNone(
-                    await mentions.apply(last_message, recent_messages, self.config)
-                )
+        await self.run_allowed(cases)
 
     @async_test
     async def test_mentions_exceeding_limit(self):
         """Messages with a higher than allowed amount of mentions."""
         cases = (
-            Case(
-                [msg("bob", 3)],
+            DisallowedCase(
+                [make_msg("bob", 3)],
                 ("bob",),
-                3
+                3,
             ),
-            Case(
-                [msg("alice", 2), msg("alice", 0), msg("alice", 1)],
+            DisallowedCase(
+                [make_msg("alice", 2), make_msg("alice", 0), make_msg("alice", 1)],
                 ("alice",),
-                3
+                3,
             ),
-            Case(
-                [msg("bob", 2), msg("alice", 3), msg("bob", 2)],
+            DisallowedCase(
+                [make_msg("bob", 2), make_msg("alice", 3), make_msg("bob", 2)],
                 ("bob",),
-                4
+                4,
             )
         )
 
-        for recent_messages, culprit, total_mentions in cases:
-            last_message = recent_messages[0]
-            relevant_messages = tuple(
-                msg
-                for msg in recent_messages
-                if msg.author == last_message.author
-            )
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        last_message = case.recent_messages[0]
+        return tuple(
+            msg
+            for msg in case.recent_messages
+            if msg.author == last_message.author
+        )
 
-            with self.subTest(
-                last_message=last_message,
-                recent_messages=recent_messages,
-                relevant_messages=relevant_messages,
-                culprit=culprit,
-                total_mentions=total_mentions,
-                cofig=self.config
-            ):
-                desired_output = (
-                    f"sent {total_mentions} mentions in {self.config['interval']}s",
-                    culprit,
-                    relevant_messages
-                )
-                self.assertTupleEqual(
-                    await mentions.apply(last_message, recent_messages, self.config),
-                    desired_output
-                )
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} mentions in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_newlines.py b/tests/bot/rules/test_newlines.py
new file mode 100644
index 000000000..d61c4609d
--- /dev/null
+++ b/tests/bot/rules/test_newlines.py
@@ -0,0 +1,105 @@
+from typing import Iterable, List
+
+from bot.rules import newlines
+from tests.bot.rules import DisallowedCase, RuleTest
+from tests.helpers import MockMessage, async_test
+
+
+def make_msg(author: str, newline_groups: List[int]) -> MockMessage:
+    """Init a MockMessage instance with `author` and content configured by `newline_groups".
+
+    Configure content by passing a list of ints, where each int `n` will generate
+    a separate group of `n` newlines.
+
+    Example:
+        newline_groups=[3, 1, 2] -> content="\n\n\n \n \n\n"
+    """
+    content = " ".join("\n" * n for n in newline_groups)
+    return MockMessage(author=author, content=content)
+
+
+class TotalNewlinesRuleTests(RuleTest):
+    """Tests the `newlines` antispam rule against allowed cases and total newline count violations."""
+
+    def setUp(self):
+        self.apply = newlines.apply
+        self.config = {
+            "max": 5,  # Max sum of newlines in relevant messages
+            "max_consecutive": 3,  # Max newlines in one group, in one message
+            "interval": 10,
+        }
+
+    @async_test
+    async def test_allows_messages_within_limit(self):
+        """Cases which do not violate the rule."""
+        cases = (
+            [make_msg("alice", [])],  # Single message with no newlines
+            [make_msg("alice", [1, 2]), make_msg("alice", [1, 1])],  # 5 newlines in 2 messages
+            [make_msg("alice", [2, 2, 1]), make_msg("bob", [2, 3])],  # 5 newlines from each author
+            [make_msg("bob", [1]), make_msg("alice", [5])],  # Alice breaks the rule, but only bob is relevant
+        )
+
+        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 = (
+            DisallowedCase(  # Alice sends a total of 6 newlines (disallowed)
+                [make_msg("alice", [2, 2]), make_msg("alice", [2])],
+                ("alice",),
+                6,
+            ),
+            DisallowedCase(  # Here we test that only alice's newlines count in the sum
+                [make_msg("alice", [2, 2]), make_msg("bob", [3]), make_msg("alice", [3])],
+                ("alice",),
+                7,
+            ),
+        )
+
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        last_author = case.recent_messages[0].author
+        return tuple(msg for msg in case.recent_messages if msg.author == last_author)
+
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} newlines in {self.config['interval']}s"
+
+
+class GroupNewlinesRuleTests(RuleTest):
+    """
+    Tests the `newlines` antispam rule against max consecutive newline violations.
+
+    As these violations yield a different error report, they require a different
+    `get_report` implementation.
+    """
+
+    def setUp(self):
+        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 = (
+            DisallowedCase(  # Bob sends a group of newlines too large
+                [make_msg("bob", [4])],
+                ("bob",),
+                4,
+            ),
+            DisallowedCase(  # Alice sends 5 in total (allowed), but 4 in one group (disallowed)
+                [make_msg("alice", [1]), make_msg("alice", [4])],
+                ("alice",),
+                4,
+            ),
+        )
+
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        last_author = case.recent_messages[0].author
+        return tuple(msg for msg in case.recent_messages if msg.author == last_author)
+
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} consecutive newlines in {self.config['interval']}s"
diff --git a/tests/bot/rules/test_role_mentions.py b/tests/bot/rules/test_role_mentions.py
new file mode 100644
index 000000000..b339cccf7
--- /dev/null
+++ b/tests/bot/rules/test_role_mentions.py
@@ -0,0 +1,57 @@
+from typing import Iterable
+
+from bot.rules import role_mentions
+from tests.bot.rules import DisallowedCase, RuleTest
+from tests.helpers import MockMessage, async_test
+
+
+def make_msg(author: str, n_mentions: int) -> MockMessage:
+    """Build a MockMessage instance with `n_mentions` role mentions."""
+    return MockMessage(author=author, role_mentions=[None] * n_mentions)
+
+
+class RoleMentionsRuleTests(RuleTest):
+    """Tests for the `role_mentions` antispam rule."""
+
+    def setUp(self):
+        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 = (
+            [make_msg("bob", 2)],
+            [make_msg("bob", 1), make_msg("alice", 1), make_msg("bob", 1)],
+        )
+
+        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 = (
+            DisallowedCase(
+                [make_msg("bob", 3)],
+                ("bob",),
+                3,
+            ),
+            DisallowedCase(
+                [make_msg("alice", 2), make_msg("bob", 2), make_msg("alice", 2)],
+                ("alice",),
+                4,
+            ),
+        )
+
+        await self.run_disallowed(cases)
+
+    def relevant_messages(self, case: DisallowedCase) -> Iterable[MockMessage]:
+        last_message = case.recent_messages[0]
+        return tuple(
+            msg
+            for msg in case.recent_messages
+            if msg.author == last_message.author
+        )
+
+    def get_report(self, case: DisallowedCase) -> str:
+        return f"sent {case.n_violations} role mentions in {self.config['interval']}s"
diff --git a/tests/bot/test_api.py b/tests/bot/test_api.py
index 5a88adc5c..bdfcc73e4 100644
--- a/tests/bot/test_api.py
+++ b/tests/bot/test_api.py
@@ -1,9 +1,7 @@
-import logging
 import unittest
-from unittest.mock import MagicMock, patch
+from unittest.mock import MagicMock
 
 from bot import api
-from tests.base import LoggingTestCase
 from tests.helpers import async_test
 
 
@@ -34,7 +32,7 @@ class APIClientTests(unittest.TestCase):
         self.assertEqual(error.response_text, "")
         self.assertIs(error.response, self.error_api_response)
 
-    def test_responde_code_error_string_representation_default_initialization(self):
+    def test_response_code_error_string_representation_default_initialization(self):
         """Test the string representation of `ResponseCodeError` initialized without text or json."""
         error = api.ResponseCodeError(response=self.error_api_response)
         self.assertEqual(str(error), f"Status: {self.error_api_response.status} Response: ")
@@ -76,61 +74,3 @@ class APIClientTests(unittest.TestCase):
             response_text=text_data
         )
         self.assertEqual(str(error), f"Status: {self.error_api_response.status} Response: {text_data}")
-
-
-class LoggingHandlerTests(LoggingTestCase):
-    """Tests the bot's API Log Handler."""
-
-    @classmethod
-    def setUpClass(cls):
-        cls.debug_log_record = logging.LogRecord(
-            name='my.logger', level=logging.DEBUG,
-            pathname='my/logger.py', lineno=666,
-            msg="Lemon wins", args=(),
-            exc_info=None
-        )
-
-        cls.trace_log_record = logging.LogRecord(
-            name='my.logger', level=logging.TRACE,
-            pathname='my/logger.py', lineno=666,
-            msg="This will not be logged", args=(),
-            exc_info=None
-        )
-
-    def setUp(self):
-        self.log_handler = api.APILoggingHandler(None)
-
-    def test_emit_appends_to_queue_with_stopped_event_loop(self):
-        """Test if `APILoggingHandler.emit` appends to queue when the event loop is not running."""
-        with patch("bot.api.APILoggingHandler.ship_off") as ship_off:
-            # Patch `ship_off` to ease testing against the return value of this coroutine.
-            ship_off.return_value = 42
-            self.log_handler.emit(self.debug_log_record)
-
-        self.assertListEqual(self.log_handler.queue, [42])
-
-    def test_emit_ignores_less_than_debug(self):
-        """`APILoggingHandler.emit` should not queue logs with a log level lower than DEBUG."""
-        self.log_handler.emit(self.trace_log_record)
-        self.assertListEqual(self.log_handler.queue, [])
-
-    def test_schedule_queued_tasks_for_empty_queue(self):
-        """`APILoggingHandler` should not schedule anything when the queue is empty."""
-        with self.assertNotLogs(level=logging.DEBUG):
-            self.log_handler.schedule_queued_tasks()
-
-    def test_schedule_queued_tasks_for_nonempty_queue(self):
-        """`APILoggingHandler` should schedule logs when the queue is not empty."""
-        log = logging.getLogger("bot.api")
-
-        with self.assertLogs(logger=log, level=logging.DEBUG) as logs, patch('asyncio.create_task') as create_task:
-            self.log_handler.queue = [555]
-            self.log_handler.schedule_queued_tasks()
-            self.assertListEqual(self.log_handler.queue, [])
-            create_task.assert_called_once_with(555)
-
-            [record] = logs.records
-            self.assertEqual(record.message, "Scheduled 1 pending logging tasks.")
-            self.assertEqual(record.levelno, logging.DEBUG)
-            self.assertEqual(record.name, 'bot.api')
-            self.assertIn('via_handler', record.__dict__)
diff --git a/tests/helpers.py b/tests/helpers.py
index 5df796c23..9d9dd5da6 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -12,6 +12,7 @@ from typing import Any, Iterable, Optional
 import discord
 from discord.ext.commands import Context
 
+from bot.api import APIClient
 from bot.bot import Bot
 
 
@@ -269,9 +270,21 @@ class MockRole(CustomMockMixin, unittest.mock.Mock, ColourMixin, HashableMixin):
     information, see the `MockGuild` docstring.
     """
     def __init__(self, **kwargs) -> None:
-        default_kwargs = {'id': next(self.discord_id), 'name': 'role', 'position': 1}
+        default_kwargs = {
+            'id': next(self.discord_id),
+            'name': 'role',
+            'position': 1,
+            'colour': discord.Colour(0xdeadbf),
+            'permissions': discord.Permissions(),
+        }
         super().__init__(spec_set=role_instance, **collections.ChainMap(kwargs, default_kwargs))
 
+        if isinstance(self.colour, int):
+            self.colour = discord.Colour(self.colour)
+
+        if isinstance(self.permissions, int):
+            self.permissions = discord.Permissions(self.permissions)
+
         if 'mention' not in kwargs:
             self.mention = f'&{self.name}'
 
@@ -324,6 +337,18 @@ class MockUser(CustomMockMixin, unittest.mock.Mock, ColourMixin, HashableMixin):
             self.mention = f"@{self.name}"
 
 
+class MockAPIClient(CustomMockMixin, unittest.mock.MagicMock):
+    """
+    A MagicMock subclass to mock APIClient objects.
+
+    Instances of this class will follow the specifications of `bot.api.APIClient` instances.
+    For more information, see the `MockGuild` docstring.
+    """
+
+    def __init__(self, **kwargs) -> None:
+        super().__init__(spec_set=APIClient, **kwargs)
+
+
 # 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
@@ -340,6 +365,7 @@ class MockBot(CustomMockMixin, unittest.mock.MagicMock):
 
     def __init__(self, **kwargs) -> None:
         super().__init__(spec_set=bot_instance, **kwargs)
+        self.api_client = MockAPIClient()
 
         # self.wait_for is *not* a coroutine function, but returns a coroutine nonetheless and
         # and should therefore be awaited. (The documentation calls it a coroutine as well, which
@@ -503,6 +529,7 @@ class MockReaction(CustomMockMixin, unittest.mock.MagicMock):
         self.emoji = kwargs.get('emoji', MockEmoji())
         self.message = kwargs.get('message', MockMessage())
         self.users = AsyncIteratorMock(kwargs.get('users', []))
+        self.__str__.return_value = str(self.emoji)
 
 
 webhook_instance = discord.Webhook(data=unittest.mock.MagicMock(), adapter=unittest.mock.MagicMock())