12 files changed, 1384 insertions, 185 deletions

diff --git a/tests/bot/cogs/moderation/test_incidents.py b/tests/bot/cogs/moderation/test_incidents.py
new file mode 100644
index 000000000..435a1cd51
--- /dev/null
+++ b/tests/bot/cogs/moderation/test_incidents.py
@@ -0,0 +1,770 @@
+import asyncio
+import enum
+import logging
+import typing as t
+import unittest
+from unittest.mock import AsyncMock, MagicMock, call, patch
+
+import aiohttp
+import discord
+
+from bot.cogs.moderation import Incidents, incidents
+from bot.constants import Colours
+from tests.helpers import (
+    MockAsyncWebhook,
+    MockAttachment,
+    MockBot,
+    MockMember,
+    MockMessage,
+    MockReaction,
+    MockRole,
+    MockTextChannel,
+    MockUser,
+)
+
+
+class MockAsyncIterable:
+    """
+    Helper for mocking asynchronous for loops.
+
+    It does not appear that the `unittest` library currently provides anything that would
+    allow us to simply mock an async iterator, such as `discord.TextChannel.history`.
+
+    We therefore write our own helper to wrap a regular synchronous iterable, and feed
+    its values via `__anext__` rather than `__next__`.
+
+    This class was written for the purposes of testing the `Incidents` cog - it may not
+    be generic enough to be placed in the `tests.helpers` module.
+    """
+
+    def __init__(self, messages: t.Iterable):
+        """Take a sync iterable to be wrapped."""
+        self.iter_messages = iter(messages)
+
+    def __aiter__(self):
+        """Return `self` as we provide the `__anext__` method."""
+        return self
+
+    async def __anext__(self):
+        """
+        Feed the next item, or raise `StopAsyncIteration`.
+
+        Since we're wrapping a sync iterator, it will communicate that it has been depleted
+        by raising a `StopIteration`. The `async for` construct does not expect it, and we
+        therefore need to substitute it for the appropriate exception type.
+        """
+        try:
+            return next(self.iter_messages)
+        except StopIteration:
+            raise StopAsyncIteration
+
+
+class MockSignal(enum.Enum):
+    A = "A"
+    B = "B"
+
+
+mock_404 = discord.NotFound(
+    response=MagicMock(aiohttp.ClientResponse),  # Mock the erroneous response
+    message="Not found",
+)
+
+
+class TestDownloadFile(unittest.IsolatedAsyncioTestCase):
+    """Collection of tests for the `download_file` helper function."""
+
+    async def test_download_file_success(self):
+        """If `to_file` succeeds, function returns the acquired `discord.File`."""
+        file = MagicMock(discord.File, filename="bigbadlemon.jpg")
+        attachment = MockAttachment(to_file=AsyncMock(return_value=file))
+
+        acquired_file = await incidents.download_file(attachment)
+        self.assertIs(file, acquired_file)
+
+    async def test_download_file_404(self):
+        """If `to_file` encounters a 404, function handles the exception & returns None."""
+        attachment = MockAttachment(to_file=AsyncMock(side_effect=mock_404))
+
+        acquired_file = await incidents.download_file(attachment)
+        self.assertIsNone(acquired_file)
+
+    async def test_download_file_fail(self):
+        """If `to_file` fails on a non-404 error, function logs the exception & returns None."""
+        arbitrary_error = discord.HTTPException(MagicMock(aiohttp.ClientResponse), "Arbitrary API error")
+        attachment = MockAttachment(to_file=AsyncMock(side_effect=arbitrary_error))
+
+        with self.assertLogs(logger=incidents.log, level=logging.ERROR):
+            acquired_file = await incidents.download_file(attachment)
+
+        self.assertIsNone(acquired_file)
+
+
+class TestMakeEmbed(unittest.IsolatedAsyncioTestCase):
+    """Collection of tests for the `make_embed` helper function."""
+
+    async def test_make_embed_actioned(self):
+        """Embed is coloured green and footer contains 'Actioned' when `outcome=Signal.ACTIONED`."""
+        embed, file = await incidents.make_embed(MockMessage(), incidents.Signal.ACTIONED, MockMember())
+
+        self.assertEqual(embed.colour.value, Colours.soft_green)
+        self.assertIn("Actioned", embed.footer.text)
+
+    async def test_make_embed_not_actioned(self):
+        """Embed is coloured red and footer contains 'Rejected' when `outcome=Signal.NOT_ACTIONED`."""
+        embed, file = await incidents.make_embed(MockMessage(), incidents.Signal.NOT_ACTIONED, MockMember())
+
+        self.assertEqual(embed.colour.value, Colours.soft_red)
+        self.assertIn("Rejected", embed.footer.text)
+
+    async def test_make_embed_content(self):
+        """Incident content appears as embed description."""
+        incident = MockMessage(content="this is an incident")
+        embed, file = await incidents.make_embed(incident, incidents.Signal.ACTIONED, MockMember())
+
+        self.assertEqual(incident.content, embed.description)
+
+    async def test_make_embed_with_attachment_succeeds(self):
+        """Incident's attachment is downloaded and displayed in the embed's image field."""
+        file = MagicMock(discord.File, filename="bigbadjoe.jpg")
+        attachment = MockAttachment(filename="bigbadjoe.jpg")
+        incident = MockMessage(content="this is an incident", attachments=[attachment])
+
+        # Patch `download_file` to return our `file`
+        with patch("bot.cogs.moderation.incidents.download_file", AsyncMock(return_value=file)):
+            embed, returned_file = await incidents.make_embed(incident, incidents.Signal.ACTIONED, MockMember())
+
+        self.assertIs(file, returned_file)
+        self.assertEqual("attachment://bigbadjoe.jpg", embed.image.url)
+
+    async def test_make_embed_with_attachment_fails(self):
+        """Incident's attachment fails to download, proxy url is linked instead."""
+        attachment = MockAttachment(proxy_url="discord.com/bigbadjoe.jpg")
+        incident = MockMessage(content="this is an incident", attachments=[attachment])
+
+        # Patch `download_file` to return None as if the download failed
+        with patch("bot.cogs.moderation.incidents.download_file", AsyncMock(return_value=None)):
+            embed, returned_file = await incidents.make_embed(incident, incidents.Signal.ACTIONED, MockMember())
+
+        self.assertIsNone(returned_file)
+
+        # The author name field is simply expected to have something in it, we do not assert the message
+        self.assertGreater(len(embed.author.name), 0)
+        self.assertEqual(embed.author.url, "discord.com/bigbadjoe.jpg")  # However, it should link the exact url
+
+
+@patch("bot.constants.Channels.incidents", 123)
+class TestIsIncident(unittest.TestCase):
+    """
+    Collection of tests for the `is_incident` helper function.
+
+    In `setUp`, we will create a mock message which should qualify as an incident. Each
+    test case will then mutate this instance to make it **not** qualify, in various ways.
+
+    Notice that we patch the #incidents channel id globally for this class.
+    """
+
+    def setUp(self) -> None:
+        """Prepare a mock message which should qualify as an incident."""
+        self.incident = MockMessage(
+            channel=MockTextChannel(id=123),
+            content="this is an incident",
+            author=MockUser(bot=False),
+            pinned=False,
+        )
+
+    def test_is_incident_true(self):
+        """Message qualifies as an incident if unchanged."""
+        self.assertTrue(incidents.is_incident(self.incident))
+
+    def check_false(self):
+        """Assert that `self.incident` does **not** qualify as an incident."""
+        self.assertFalse(incidents.is_incident(self.incident))
+
+    def test_is_incident_false_channel(self):
+        """Message doesn't qualify if sent outside of #incidents."""
+        self.incident.channel = MockTextChannel(id=456)
+        self.check_false()
+
+    def test_is_incident_false_content(self):
+        """Message doesn't qualify if content begins with hash symbol."""
+        self.incident.content = "# this is a comment message"
+        self.check_false()
+
+    def test_is_incident_false_author(self):
+        """Message doesn't qualify if author is a bot."""
+        self.incident.author = MockUser(bot=True)
+        self.check_false()
+
+    def test_is_incident_false_pinned(self):
+        """Message doesn't qualify if it is pinned."""
+        self.incident.pinned = True
+        self.check_false()
+
+
+class TestOwnReactions(unittest.TestCase):
+    """Assertions for the `own_reactions` function."""
+
+    def test_own_reactions(self):
+        """Only bot's own emoji are extracted from the input incident."""
+        reactions = (
+            MockReaction(emoji="A", me=True),
+            MockReaction(emoji="B", me=True),
+            MockReaction(emoji="C", me=False),
+        )
+        message = MockMessage(reactions=reactions)
+        self.assertSetEqual(incidents.own_reactions(message), {"A", "B"})
+
+
+@patch("bot.cogs.moderation.incidents.ALL_SIGNALS", {"A", "B"})
+class TestHasSignals(unittest.TestCase):
+    """
+    Assertions for the `has_signals` function.
+
+    We patch `ALL_SIGNALS` globally. Each test function then patches `own_reactions`
+    as appropriate.
+    """
+
+    def test_has_signals_true(self):
+        """True when `own_reactions` returns all emoji in `ALL_SIGNALS`."""
+        message = MockMessage()
+        own_reactions = MagicMock(return_value={"A", "B"})
+
+        with patch("bot.cogs.moderation.incidents.own_reactions", own_reactions):
+            self.assertTrue(incidents.has_signals(message))
+
+    def test_has_signals_false(self):
+        """False when `own_reactions` does not return all emoji in `ALL_SIGNALS`."""
+        message = MockMessage()
+        own_reactions = MagicMock(return_value={"A", "C"})
+
+        with patch("bot.cogs.moderation.incidents.own_reactions", own_reactions):
+            self.assertFalse(incidents.has_signals(message))
+
+
+@patch("bot.cogs.moderation.incidents.Signal", MockSignal)
+class TestAddSignals(unittest.IsolatedAsyncioTestCase):
+    """
+    Assertions for the `add_signals` coroutine.
+
+    These are all fairly similar and could go into a single test function, but I found the
+    patching & sub-testing fairly awkward in that case and decided to split them up
+    to avoid unnecessary syntax noise.
+    """
+
+    def setUp(self):
+        """Prepare a mock incident message for tests to use."""
+        self.incident = MockMessage()
+
+    @patch("bot.cogs.moderation.incidents.own_reactions", MagicMock(return_value=set()))
+    async def test_add_signals_missing(self):
+        """All emoji are added when none are present."""
+        await incidents.add_signals(self.incident)
+        self.incident.add_reaction.assert_has_calls([call("A"), call("B")])
+
+    @patch("bot.cogs.moderation.incidents.own_reactions", MagicMock(return_value={"A"}))
+    async def test_add_signals_partial(self):
+        """Only missing emoji are added when some are present."""
+        await incidents.add_signals(self.incident)
+        self.incident.add_reaction.assert_has_calls([call("B")])
+
+    @patch("bot.cogs.moderation.incidents.own_reactions", MagicMock(return_value={"A", "B"}))
+    async def test_add_signals_present(self):
+        """No emoji are added when all are present."""
+        await incidents.add_signals(self.incident)
+        self.incident.add_reaction.assert_not_called()
+
+
+class TestIncidents(unittest.IsolatedAsyncioTestCase):
+    """
+    Tests for bound methods of the `Incidents` cog.
+
+    Use this as a base class for `Incidents` tests - it will prepare a fresh instance
+    for each test function, but not make any assertions on its own. Tests can mutate
+    the instance as they wish.
+    """
+
+    def setUp(self):
+        """
+        Prepare a fresh `Incidents` instance for each test.
+
+        Note that this will not schedule `crawl_incidents` in the background, as everything
+        is being mocked. The `crawl_task` attribute will end up being None.
+        """
+        self.cog_instance = Incidents(MockBot())
+
+
+@patch("asyncio.sleep", AsyncMock())  # Prevent the coro from sleeping to speed up the test
+class TestCrawlIncidents(TestIncidents):
+    """
+    Tests for the `Incidents.crawl_incidents` coroutine.
+
+    Apart from `test_crawl_incidents_waits_until_cache_ready`, all tests in this class
+    will patch the return values of `is_incident` and `has_signal` and then observe
+    whether the `AsyncMock` for `add_signals` was awaited or not.
+
+    The `add_signals` mock is added by each test separately to ensure it is clean (has not
+    been awaited by another test yet). The mock can be reset, but this appears to be the
+    cleaner way.
+
+    For each test, we inject a mock channel with a history of 1 message only (see: `setUp`).
+    """
+
+    def setUp(self):
+        """For each test, ensure `bot.get_channel` returns a channel with 1 arbitrary message."""
+        super().setUp()  # First ensure we get `cog_instance` from parent
+
+        incidents_history = MagicMock(return_value=MockAsyncIterable([MockMessage()]))
+        self.cog_instance.bot.get_channel = MagicMock(return_value=MockTextChannel(history=incidents_history))
+
+    async def test_crawl_incidents_waits_until_cache_ready(self):
+        """
+        The coroutine will await the `wait_until_guild_available` event.
+
+        Since this task is schedule in the `__init__`, it is critical that it waits for the
+        cache to be ready, so that it can safely get the #incidents channel.
+        """
+        await self.cog_instance.crawl_incidents()
+        self.cog_instance.bot.wait_until_guild_available.assert_awaited()
+
+    @patch("bot.cogs.moderation.incidents.add_signals", AsyncMock())
+    @patch("bot.cogs.moderation.incidents.is_incident", MagicMock(return_value=False))  # Message doesn't qualify
+    @patch("bot.cogs.moderation.incidents.has_signals", MagicMock(return_value=False))
+    async def test_crawl_incidents_noop_if_is_not_incident(self):
+        """Signals are not added for a non-incident message."""
+        await self.cog_instance.crawl_incidents()
+        incidents.add_signals.assert_not_awaited()
+
+    @patch("bot.cogs.moderation.incidents.add_signals", AsyncMock())
+    @patch("bot.cogs.moderation.incidents.is_incident", MagicMock(return_value=True))  # Message qualifies
+    @patch("bot.cogs.moderation.incidents.has_signals", MagicMock(return_value=True))  # But already has signals
+    async def test_crawl_incidents_noop_if_message_already_has_signals(self):
+        """Signals are not added for messages which already have them."""
+        await self.cog_instance.crawl_incidents()
+        incidents.add_signals.assert_not_awaited()
+
+    @patch("bot.cogs.moderation.incidents.add_signals", AsyncMock())
+    @patch("bot.cogs.moderation.incidents.is_incident", MagicMock(return_value=True))  # Message qualifies
+    @patch("bot.cogs.moderation.incidents.has_signals", MagicMock(return_value=False))  # And doesn't have signals
+    async def test_crawl_incidents_add_signals_called(self):
+        """Message has signals added as it does not have them yet and qualifies as an incident."""
+        await self.cog_instance.crawl_incidents()
+        incidents.add_signals.assert_awaited_once()
+
+
+class TestArchive(TestIncidents):
+    """Tests for the `Incidents.archive` coroutine."""
+
+    async def test_archive_webhook_not_found(self):
+        """
+        Method recovers and returns False when the webhook is not found.
+
+        Implicitly, this also tests that the error is handled internally and doesn't
+        propagate out of the method, which is just as important.
+        """
+        self.cog_instance.bot.fetch_webhook = AsyncMock(side_effect=mock_404)
+        self.assertFalse(
+            await self.cog_instance.archive(incident=MockMessage(), outcome=MagicMock(), actioned_by=MockMember())
+        )
+
+    async def test_archive_relays_incident(self):
+        """
+        If webhook is found, method relays `incident` properly.
+
+        This test will assert that the fetched webhook's `send` method is fed the correct arguments,
+        and that the `archive` method returns True.
+        """
+        webhook = MockAsyncWebhook()
+        self.cog_instance.bot.fetch_webhook = AsyncMock(return_value=webhook)  # Patch in our webhook
+
+        # Define our own `incident` to be archived
+        incident = MockMessage(
+            content="this is an incident",
+            author=MockUser(name="author_name", avatar_url="author_avatar"),
+            id=123,
+        )
+        built_embed = MagicMock(discord.Embed, id=123)  # We patch `make_embed` to return this
+
+        with patch("bot.cogs.moderation.incidents.make_embed", AsyncMock(return_value=(built_embed, None))):
+            archive_return = await self.cog_instance.archive(incident, MagicMock(value="A"), MockMember())
+
+        # Now we check that the webhook was given the correct args, and that `archive` returned True
+        webhook.send.assert_called_once_with(
+            embed=built_embed,
+            username="author_name",
+            avatar_url="author_avatar",
+            file=None,
+        )
+        self.assertTrue(archive_return)
+
+    async def test_archive_clyde_username(self):
+        """
+        The archive webhook username is cleansed using `sub_clyde`.
+
+        Discord will reject any webhook with "clyde" in the username field, as it impersonates
+        the official Clyde bot. Since we do not control what the username will be (the incident
+        author name is used), we must ensure the name is cleansed, otherwise the relay may fail.
+
+        This test assumes the username is passed as a kwarg. If this test fails, please review
+        whether the passed argument is being retrieved correctly.
+        """
+        webhook = MockAsyncWebhook()
+        self.cog_instance.bot.fetch_webhook = AsyncMock(return_value=webhook)
+
+        message_from_clyde = MockMessage(author=MockUser(name="clyde the great"))
+        await self.cog_instance.archive(message_from_clyde, MagicMock(incidents.Signal), MockMember())
+
+        self.assertNotIn("clyde", webhook.send.call_args.kwargs["username"])
+
+
+class TestMakeConfirmationTask(TestIncidents):
+    """
+    Tests for the `Incidents.make_confirmation_task` method.
+
+    Writing tests for this method is difficult, as it mostly just delegates the provided
+    information elsewhere. There is very little internal logic. Whether our approach
+    works conceptually is difficult to prove using unit tests.
+    """
+
+    def test_make_confirmation_task_check(self):
+        """
+        The internal check will recognize the passed incident.
+
+        This is a little tricky - we first pass a message with a specific `id` in, and then
+        retrieve the built check from the `call_args` of the `wait_for` method. This relies
+        on the check being passed as a kwarg.
+
+        Once the check is retrieved, we assert that it gives True for our incident's `id`,
+        and False for any other.
+
+        If this function begins to fail, first check that `created_check` is being retrieved
+        correctly. It should be the function that is built locally in the tested method.
+        """
+        self.cog_instance.make_confirmation_task(MockMessage(id=123))
+
+        self.cog_instance.bot.wait_for.assert_called_once()
+        created_check = self.cog_instance.bot.wait_for.call_args.kwargs["check"]
+
+        # The `message_id` matches the `id` of our incident
+        self.assertTrue(created_check(payload=MagicMock(message_id=123)))
+
+        # This `message_id` does not match
+        self.assertFalse(created_check(payload=MagicMock(message_id=0)))
+
+
+@patch("bot.cogs.moderation.incidents.ALLOWED_ROLES", {1, 2})
+@patch("bot.cogs.moderation.incidents.Incidents.make_confirmation_task", AsyncMock())  # Generic awaitable
+class TestProcessEvent(TestIncidents):
+    """Tests for the `Incidents.process_event` coroutine."""
+
+    async def test_process_event_bad_role(self):
+        """The reaction is removed when the author lacks all allowed roles."""
+        incident = MockMessage()
+        member = MockMember(roles=[MockRole(id=0)])  # Must have role 1 or 2
+
+        await self.cog_instance.process_event("reaction", incident, member)
+        incident.remove_reaction.assert_called_once_with("reaction", member)
+
+    async def test_process_event_bad_emoji(self):
+        """
+        The reaction is removed when an invalid emoji is used.
+
+        This requires that we pass in a `member` with valid roles, as we need the role check
+        to succeed.
+        """
+        incident = MockMessage()
+        member = MockMember(roles=[MockRole(id=1)])  # Member has allowed role
+
+        await self.cog_instance.process_event("invalid_signal", incident, member)
+        incident.remove_reaction.assert_called_once_with("invalid_signal", member)
+
+    async def test_process_event_no_archive_on_investigating(self):
+        """Message is not archived on `Signal.INVESTIGATING`."""
+        with patch("bot.cogs.moderation.incidents.Incidents.archive", AsyncMock()) as mocked_archive:
+            await self.cog_instance.process_event(
+                reaction=incidents.Signal.INVESTIGATING.value,
+                incident=MockMessage(),
+                member=MockMember(roles=[MockRole(id=1)]),
+            )
+
+        mocked_archive.assert_not_called()
+
+    async def test_process_event_no_delete_if_archive_fails(self):
+        """
+        Original message is not deleted when `Incidents.archive` returns False.
+
+        This is the way of signaling that the relay failed, and we should not remove the original,
+        as that would result in losing the incident record.
+        """
+        incident = MockMessage()
+
+        with patch("bot.cogs.moderation.incidents.Incidents.archive", AsyncMock(return_value=False)):
+            await self.cog_instance.process_event(
+                reaction=incidents.Signal.ACTIONED.value,
+                incident=incident,
+                member=MockMember(roles=[MockRole(id=1)])
+            )
+
+        incident.delete.assert_not_called()
+
+    async def test_process_event_confirmation_task_is_awaited(self):
+        """Task given by `Incidents.make_confirmation_task` is awaited before method exits."""
+        mock_task = AsyncMock()
+
+        with patch("bot.cogs.moderation.incidents.Incidents.make_confirmation_task", mock_task):
+            await self.cog_instance.process_event(
+                reaction=incidents.Signal.ACTIONED.value,
+                incident=MockMessage(),
+                member=MockMember(roles=[MockRole(id=1)])
+            )
+
+        mock_task.assert_awaited()
+
+    async def test_process_event_confirmation_task_timeout_is_handled(self):
+        """
+        Confirmation task `asyncio.TimeoutError` is handled gracefully.
+
+        We have `make_confirmation_task` return a mock with a side effect, and then catch the
+        exception should it propagate out of `process_event`. This is so that we can then manually
+        fail the test with a more informative message than just the plain traceback.
+        """
+        mock_task = AsyncMock(side_effect=asyncio.TimeoutError())
+
+        try:
+            with patch("bot.cogs.moderation.incidents.Incidents.make_confirmation_task", mock_task):
+                await self.cog_instance.process_event(
+                    reaction=incidents.Signal.ACTIONED.value,
+                    incident=MockMessage(),
+                    member=MockMember(roles=[MockRole(id=1)])
+                )
+        except asyncio.TimeoutError:
+            self.fail("TimeoutError was not handled gracefully, and propagated out of `process_event`!")
+
+
+class TestResolveMessage(TestIncidents):
+    """Tests for the `Incidents.resolve_message` coroutine."""
+
+    async def test_resolve_message_pass_message_id(self):
+        """Method will call `_get_message` with the passed `message_id`."""
+        await self.cog_instance.resolve_message(123)
+        self.cog_instance.bot._connection._get_message.assert_called_once_with(123)
+
+    async def test_resolve_message_in_cache(self):
+        """
+        No API call is made if the queried message exists in the cache.
+
+        We mock the `_get_message` return value regardless of input. Whether it finds the message
+        internally is considered d.py's responsibility, not ours.
+        """
+        cached_message = MockMessage(id=123)
+        self.cog_instance.bot._connection._get_message = MagicMock(return_value=cached_message)
+
+        return_value = await self.cog_instance.resolve_message(123)
+
+        self.assertIs(return_value, cached_message)
+        self.cog_instance.bot.get_channel.assert_not_called()  # The `fetch_message` line was never hit
+
+    async def test_resolve_message_not_in_cache(self):
+        """
+        The message is retrieved from the API if it isn't cached.
+
+        This is desired behaviour for messages which exist, but were sent before the bot's
+        current session.
+        """
+        self.cog_instance.bot._connection._get_message = MagicMock(return_value=None)  # Cache returns None
+
+        # API returns our message
+        uncached_message = MockMessage()
+        fetch_message = AsyncMock(return_value=uncached_message)
+        self.cog_instance.bot.get_channel = MagicMock(return_value=MockTextChannel(fetch_message=fetch_message))
+
+        retrieved_message = await self.cog_instance.resolve_message(123)
+        self.assertIs(retrieved_message, uncached_message)
+
+    async def test_resolve_message_doesnt_exist(self):
+        """
+        If the API returns a 404, the function handles it gracefully and returns None.
+
+        This is an edge-case happening with racing events - event A will relay the message
+        to the archive and delete the original. Once event B acquires the `event_lock`,
+        it will not find the message in the cache, and will ask the API.
+        """
+        self.cog_instance.bot._connection._get_message = MagicMock(return_value=None)  # Cache returns None
+
+        fetch_message = AsyncMock(side_effect=mock_404)
+        self.cog_instance.bot.get_channel = MagicMock(return_value=MockTextChannel(fetch_message=fetch_message))
+
+        self.assertIsNone(await self.cog_instance.resolve_message(123))
+
+    async def test_resolve_message_fetch_fails(self):
+        """
+        Non-404 errors are handled, logged & None is returned.
+
+        In contrast with a 404, this should make an error-level log. We assert that at least
+        one such log was made - we do not make any assertions about the log's message.
+        """
+        self.cog_instance.bot._connection._get_message = MagicMock(return_value=None)  # Cache returns None
+
+        arbitrary_error = discord.HTTPException(
+            response=MagicMock(aiohttp.ClientResponse),
+            message="Arbitrary error",
+        )
+        fetch_message = AsyncMock(side_effect=arbitrary_error)
+        self.cog_instance.bot.get_channel = MagicMock(return_value=MockTextChannel(fetch_message=fetch_message))
+
+        with self.assertLogs(logger=incidents.log, level=logging.ERROR):
+            self.assertIsNone(await self.cog_instance.resolve_message(123))
+
+
+@patch("bot.constants.Channels.incidents", 123)
+class TestOnRawReactionAdd(TestIncidents):
+    """
+    Tests for the `Incidents.on_raw_reaction_add` listener.
+
+    Writing tests for this listener comes with additional complexity due to the listener
+    awaiting the `crawl_task` task. See `asyncSetUp` for further details, which attempts
+    to make unit testing this function possible.
+    """
+
+    def setUp(self):
+        """
+        Prepare & assign `payload` attribute.
+
+        This attribute represents an *ideal* payload which will not be rejected by the
+        listener. As each test will receive a fresh instance, it can be mutated to
+        observe how the listener's behaviour changes with different attributes on
+        the passed payload.
+        """
+        super().setUp()  # Ensure `cog_instance` is assigned
+
+        self.payload = MagicMock(
+            discord.RawReactionActionEvent,
+            channel_id=123,  # Patched at class level
+            message_id=456,
+            member=MockMember(bot=False),
+            emoji="reaction",
+        )
+
+    async def asyncSetUp(self):  # noqa: N802
+        """
+        Prepare an empty task and assign it as `crawl_task`.
+
+        It appears that the `unittest` framework does not provide anything for mocking
+        asyncio tasks. An `AsyncMock` instance can be called and then awaited, however,
+        it does not provide the `done` method or any other parts of the `asyncio.Task`
+        interface.
+
+        Although we do not need to make any assertions about the task itself while
+        testing the listener, the code will still await it and call the `done` method,
+        and so we must inject something that will not fail on either action.
+
+        Note that this is done in an `asyncSetUp`, which runs after `setUp`.
+        The justification is that creating an actual task requires the event
+        loop to be ready, which is not the case in the `setUp`.
+        """
+        mock_task = asyncio.create_task(AsyncMock()())  # Mock async func, then a coro
+        self.cog_instance.crawl_task = mock_task
+
+    async def test_on_raw_reaction_add_wrong_channel(self):
+        """
+        Events outside of #incidents will be ignored.
+
+        We check this by asserting that `resolve_message` was never queried.
+        """
+        self.payload.channel_id = 0
+        self.cog_instance.resolve_message = AsyncMock()
+
+        await self.cog_instance.on_raw_reaction_add(self.payload)
+        self.cog_instance.resolve_message.assert_not_called()
+
+    async def test_on_raw_reaction_add_user_is_bot(self):
+        """
+        Events dispatched by bot accounts will be ignored.
+
+        We check this by asserting that `resolve_message` was never queried.
+        """
+        self.payload.member = MockMember(bot=True)
+        self.cog_instance.resolve_message = AsyncMock()
+
+        await self.cog_instance.on_raw_reaction_add(self.payload)
+        self.cog_instance.resolve_message.assert_not_called()
+
+    async def test_on_raw_reaction_add_message_doesnt_exist(self):
+        """
+        Listener gracefully handles the case where `resolve_message` gives None.
+
+        We check this by asserting that `process_event` was never called.
+        """
+        self.cog_instance.process_event = AsyncMock()
+        self.cog_instance.resolve_message = AsyncMock(return_value=None)
+
+        await self.cog_instance.on_raw_reaction_add(self.payload)
+        self.cog_instance.process_event.assert_not_called()
+
+    async def test_on_raw_reaction_add_message_is_not_an_incident(self):
+        """
+        The event won't be processed if the related message is not an incident.
+
+        This is an edge-case that can happen if someone manually leaves a reaction
+        on a pinned message, or a comment.
+
+        We check this by asserting that `process_event` was never called.
+        """
+        self.cog_instance.process_event = AsyncMock()
+        self.cog_instance.resolve_message = AsyncMock(return_value=MockMessage())
+
+        with patch("bot.cogs.moderation.incidents.is_incident", MagicMock(return_value=False)):
+            await self.cog_instance.on_raw_reaction_add(self.payload)
+
+        self.cog_instance.process_event.assert_not_called()
+
+    async def test_on_raw_reaction_add_valid_event_is_processed(self):
+        """
+        If the reaction event is valid, it is passed to `process_event`.
+
+        This is the case when everything goes right:
+            * The reaction was placed in #incidents, and not by a bot
+            * The message was found successfully
+            * The message qualifies as an incident
+
+        Additionally, we check that all arguments were passed as expected.
+        """
+        incident = MockMessage(id=1)
+
+        self.cog_instance.process_event = AsyncMock()
+        self.cog_instance.resolve_message = AsyncMock(return_value=incident)
+
+        with patch("bot.cogs.moderation.incidents.is_incident", MagicMock(return_value=True)):
+            await self.cog_instance.on_raw_reaction_add(self.payload)
+
+        self.cog_instance.process_event.assert_called_with(
+            "reaction",  # Defined in `self.payload`
+            incident,
+            self.payload.member,
+        )
+
+
+class TestOnMessage(TestIncidents):
+    """
+    Tests for the `Incidents.on_message` listener.
+
+    Notice the decorators mocking the `is_incident` return value. The `is_incidents`
+    function is tested in `TestIsIncident` - here we do not worry about it.
+    """
+
+    @patch("bot.cogs.moderation.incidents.is_incident", MagicMock(return_value=True))
+    async def test_on_message_incident(self):
+        """Messages qualifying as incidents are passed to `add_signals`."""
+        incident = MockMessage()
+
+        with patch("bot.cogs.moderation.incidents.add_signals", AsyncMock()) as mock_add_signals:
+            await self.cog_instance.on_message(incident)
+
+        mock_add_signals.assert_called_once_with(incident)
+
+    @patch("bot.cogs.moderation.incidents.is_incident", MagicMock(return_value=False))
+    async def test_on_message_non_incident(self):
+        """Messages not qualifying as incidents are ignored."""
+        with patch("bot.cogs.moderation.incidents.add_signals", AsyncMock()) as mock_add_signals:
+            await self.cog_instance.on_message(MockMessage())
+
+        mock_add_signals.assert_not_called()
diff --git a/tests/bot/cogs/moderation/test_silence.py b/tests/bot/cogs/moderation/test_silence.py
index 3fd149f04..ab3d0742a 100644
--- a/tests/bot/cogs/moderation/test_silence.py
+++ b/tests/bot/cogs/moderation/test_silence.py
@@ -127,10 +127,20 @@ class SilenceTests(unittest.IsolatedAsyncioTestCase):
             self.ctx.reset_mock()
 
     async def test_unsilence_sent_correct_discord_message(self):
-        """Proper reply after a successful unsilence."""
-        with mock.patch.object(self.cog, "_unsilence", return_value=True):
-            await self.cog.unsilence.callback(self.cog, self.ctx)
-            self.ctx.send.assert_called_once_with(f"{Emojis.check_mark} unsilenced current channel.")
+        """Check if proper message was sent when unsilencing channel."""
+        test_cases = (
+            (True, f"{Emojis.check_mark} unsilenced current channel."),
+            (False, f"{Emojis.cross_mark} current channel was not silenced.")
+        )
+        for _unsilence_patch_return, result_message in test_cases:
+            with self.subTest(
+                starting_silenced_state=_unsilence_patch_return,
+                result_message=result_message
+            ):
+                with mock.patch.object(self.cog, "_unsilence", return_value=_unsilence_patch_return):
+                    await self.cog.unsilence.callback(self.cog, self.ctx)
+                    self.ctx.send.assert_called_once_with(result_message)
+            self.ctx.reset_mock()
 
     async def test_silence_private_for_false(self):
         """Permissions are not set and `False` is returned in an already silenced channel."""
diff --git a/tests/bot/cogs/sync/test_cog.py b/tests/bot/cogs/sync/test_cog.py
index 14fd909c4..120bc991d 100644
--- a/tests/bot/cogs/sync/test_cog.py
+++ b/tests/bot/cogs/sync/test_cog.py
@@ -131,6 +131,15 @@ class SyncCogListenerTests(SyncCogTestCase):
         super().setUp()
         self.cog.patch_user = mock.AsyncMock(spec_set=self.cog.patch_user)
 
+        self.guild_id_patcher = mock.patch("bot.cogs.sync.cog.constants.Guild.id", 5)
+        self.guild_id = self.guild_id_patcher.start()
+
+        self.guild = helpers.MockGuild(id=self.guild_id)
+        self.other_guild = helpers.MockGuild(id=0)
+
+    def tearDown(self):
+        self.guild_id_patcher.stop()
+
     async def test_sync_cog_on_guild_role_create(self):
         """A POST request should be sent with the new role's data."""
         self.assertTrue(self.cog.on_guild_role_create.__cog_listener__)
@@ -142,20 +151,32 @@ class SyncCogListenerTests(SyncCogTestCase):
             "permissions": 8,
             "position": 23,
         }
-        role = helpers.MockRole(**role_data)
+        role = helpers.MockRole(**role_data, guild=self.guild)
         await self.cog.on_guild_role_create(role)
 
         self.bot.api_client.post.assert_called_once_with("bot/roles", json=role_data)
 
+    async def test_sync_cog_on_guild_role_create_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        role = helpers.MockRole(guild=self.other_guild)
+        await self.cog.on_guild_role_create(role)
+        self.bot.api_client.post.assert_not_awaited()
+
     async def test_sync_cog_on_guild_role_delete(self):
         """A DELETE request should be sent."""
         self.assertTrue(self.cog.on_guild_role_delete.__cog_listener__)
 
-        role = helpers.MockRole(id=99)
+        role = helpers.MockRole(id=99, guild=self.guild)
         await self.cog.on_guild_role_delete(role)
 
         self.bot.api_client.delete.assert_called_once_with("bot/roles/99")
 
+    async def test_sync_cog_on_guild_role_delete_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        role = helpers.MockRole(guild=self.other_guild)
+        await self.cog.on_guild_role_delete(role)
+        self.bot.api_client.delete.assert_not_awaited()
+
     async def test_sync_cog_on_guild_role_update(self):
         """A PUT request should be sent if the colour, name, permissions, or position changes."""
         self.assertTrue(self.cog.on_guild_role_update.__cog_listener__)
@@ -180,8 +201,8 @@ class SyncCogListenerTests(SyncCogTestCase):
                     after_role_data = role_data.copy()
                     after_role_data[attribute] = 876
 
-                    before_role = helpers.MockRole(**role_data)
-                    after_role = helpers.MockRole(**after_role_data)
+                    before_role = helpers.MockRole(**role_data, guild=self.guild)
+                    after_role = helpers.MockRole(**after_role_data, guild=self.guild)
 
                     await self.cog.on_guild_role_update(before_role, after_role)
 
@@ -193,31 +214,43 @@ class SyncCogListenerTests(SyncCogTestCase):
                     else:
                         self.bot.api_client.put.assert_not_called()
 
+    async def test_sync_cog_on_guild_role_update_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        role = helpers.MockRole(guild=self.other_guild)
+        await self.cog.on_guild_role_update(role, role)
+        self.bot.api_client.put.assert_not_awaited()
+
     async def test_sync_cog_on_member_remove(self):
-        """Member should patched to set in_guild as False."""
+        """Member should be patched to set in_guild as False."""
         self.assertTrue(self.cog.on_member_remove.__cog_listener__)
 
-        member = helpers.MockMember()
+        member = helpers.MockMember(guild=self.guild)
         await self.cog.on_member_remove(member)
 
         self.cog.patch_user.assert_called_once_with(
             member.id,
-            updated_information={"in_guild": False}
+            json={"in_guild": False}
         )
 
+    async def test_sync_cog_on_member_remove_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        member = helpers.MockMember(guild=self.other_guild)
+        await self.cog.on_member_remove(member)
+        self.cog.patch_user.assert_not_awaited()
+
     async def test_sync_cog_on_member_update_roles(self):
         """Members should be patched if their roles have changed."""
         self.assertTrue(self.cog.on_member_update.__cog_listener__)
 
         # Roles are intentionally unsorted.
         before_roles = [helpers.MockRole(id=12), helpers.MockRole(id=30), helpers.MockRole(id=20)]
-        before_member = helpers.MockMember(roles=before_roles)
-        after_member = helpers.MockMember(roles=before_roles[1:])
+        before_member = helpers.MockMember(roles=before_roles, guild=self.guild)
+        after_member = helpers.MockMember(roles=before_roles[1:], guild=self.guild)
 
         await self.cog.on_member_update(before_member, after_member)
 
         data = {"roles": sorted(role.id for role in after_member.roles)}
-        self.cog.patch_user.assert_called_once_with(after_member.id, updated_information=data)
+        self.cog.patch_user.assert_called_once_with(after_member.id, json=data)
 
     async def test_sync_cog_on_member_update_other(self):
         """Members should not be patched if other attributes have changed."""
@@ -233,13 +266,19 @@ class SyncCogListenerTests(SyncCogTestCase):
             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})
+                before_member = helpers.MockMember(**{attribute: old_value}, guild=self.guild)
+                after_member = helpers.MockMember(**{attribute: new_value}, guild=self.guild)
 
                 await self.cog.on_member_update(before_member, after_member)
 
                 self.cog.patch_user.assert_not_called()
 
+    async def test_sync_cog_on_member_update_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        member = helpers.MockMember(guild=self.other_guild)
+        await self.cog.on_member_update(member, member)
+        self.cog.patch_user.assert_not_awaited()
+
     async def test_sync_cog_on_user_update(self):
         """A user should be patched only if the name, discriminator, or avatar changes."""
         self.assertTrue(self.cog.on_user_update.__cog_listener__)
@@ -272,12 +311,15 @@ class SyncCogListenerTests(SyncCogTestCase):
 
                     # 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])
+                    self.assertEqual(call_args.args[0], after_user.id)
+                    self.assertIn("json", call_args.kwargs)
+
+                    self.assertIn("ignore_404", call_args.kwargs)
+                    self.assertTrue(call_args.kwargs["ignore_404"])
 
-                    updated_information = call_args[1]["updated_information"]
-                    self.assertIn(api_field, updated_information)
-                    self.assertEqual(updated_information[api_field], api_value)
+                    json = call_args.kwargs["json"]
+                    self.assertIn(api_field, json)
+                    self.assertEqual(json[api_field], api_value)
                 else:
                     self.cog.patch_user.assert_not_called()
 
@@ -290,6 +332,7 @@ class SyncCogListenerTests(SyncCogTestCase):
         member = helpers.MockMember(
             discriminator="1234",
             roles=[helpers.MockRole(id=22), helpers.MockRole(id=12)],
+            guild=self.guild,
         )
 
         data = {
@@ -334,6 +377,13 @@ class SyncCogListenerTests(SyncCogTestCase):
 
         self.bot.api_client.post.assert_not_called()
 
+    async def test_sync_cog_on_member_join_ignores_guilds(self):
+        """Events from other guilds should be ignored."""
+        member = helpers.MockMember(guild=self.other_guild)
+        await self.cog.on_member_join(member)
+        self.bot.api_client.post.assert_not_awaited()
+        self.bot.api_client.put.assert_not_awaited()
+
 
 class SyncCogCommandTests(SyncCogTestCase, CommandTestCase):
     """Tests for the commands in the Sync cog."""
diff --git a/tests/bot/cogs/test_duck_pond.py b/tests/bot/cogs/test_duck_pond.py
index a8c0107c6..cfe10aebf 100644
--- a/tests/bot/cogs/test_duck_pond.py
+++ b/tests/bot/cogs/test_duck_pond.py
@@ -129,38 +129,6 @@ class DuckPondTests(base.LoggingTestsMixin, unittest.IsolatedAsyncioTestCase):
             ):
                 self.assertEqual(expected_return, actual_return)
 
-    def test_send_webhook_correctly_passes_on_arguments(self):
-        """The `send_webhook` method should pass the arguments to the webhook correctly."""
-        self.cog.webhook = helpers.MockAsyncWebhook()
-
-        content = "fake content"
-        username = "fake username"
-        avatar_url = "fake avatar_url"
-        embed = "fake embed"
-
-        asyncio.run(self.cog.send_webhook(content, username, avatar_url, embed))
-
-        self.cog.webhook.send.assert_called_once_with(
-            content=content,
-            username=username,
-            avatar_url=avatar_url,
-            embed=embed
-        )
-
-    def test_send_webhook_logs_when_sending_message_fails(self):
-        """The `send_webhook` method should catch a `discord.HTTPException` and log accordingly."""
-        self.cog.webhook = helpers.MockAsyncWebhook()
-        self.cog.webhook.send.side_effect = discord.HTTPException(response=MagicMock(), message="Something failed.")
-
-        log = logging.getLogger('bot.cogs.duck_pond')
-        with self.assertLogs(logger=log, level=logging.ERROR) as log_watcher:
-            asyncio.run(self.cog.send_webhook())
-
-        self.assertEqual(len(log_watcher.records), 1)
-
-        record = log_watcher.records[0]
-        self.assertEqual(record.levelno, logging.ERROR)
-
     def _get_reaction(
         self,
         emoji: typing.Union[str, helpers.MockEmoji],
@@ -280,16 +248,20 @@ class DuckPondTests(base.LoggingTestsMixin, unittest.IsolatedAsyncioTestCase):
 
     async def test_relay_message_correctly_relays_content_and_attachments(self):
         """The `relay_message` method should correctly relay message content and attachments."""
-        send_webhook_path = f"{MODULE_PATH}.DuckPond.send_webhook"
+        send_webhook_path = f"{MODULE_PATH}.send_webhook"
         send_attachments_path = f"{MODULE_PATH}.send_attachments"
+        author = MagicMock(
+            display_name="x",
+            avatar_url="https://"
+        )
 
         self.cog.webhook = helpers.MockAsyncWebhook()
 
         test_values = (
-            (helpers.MockMessage(clean_content="", attachments=[]), False, False),
-            (helpers.MockMessage(clean_content="message", attachments=[]), True, False),
-            (helpers.MockMessage(clean_content="", attachments=["attachment"]), False, True),
-            (helpers.MockMessage(clean_content="message", attachments=["attachment"]), True, True),
+            (helpers.MockMessage(author=author, clean_content="", attachments=[]), False, False),
+            (helpers.MockMessage(author=author, clean_content="message", attachments=[]), True, False),
+            (helpers.MockMessage(author=author, clean_content="", attachments=["attachment"]), False, True),
+            (helpers.MockMessage(author=author, clean_content="message", attachments=["attachment"]), True, True),
         )
 
         for message, expect_webhook_call, expect_attachment_call in test_values:
@@ -314,14 +286,14 @@ class DuckPondTests(base.LoggingTestsMixin, unittest.IsolatedAsyncioTestCase):
 
         for side_effect in side_effects:  # pragma: no cover
             send_attachments.side_effect = side_effect
-            with patch(f"{MODULE_PATH}.DuckPond.send_webhook", new_callable=AsyncMock) as send_webhook:
+            with patch(f"{MODULE_PATH}.send_webhook", new_callable=AsyncMock) as send_webhook:
                 with self.subTest(side_effect=type(side_effect).__name__):
                     with self.assertNotLogs(logger=log, level=logging.ERROR):
                         await self.cog.relay_message(message)
 
                     self.assertEqual(send_webhook.call_count, 2)
 
-    @patch(f"{MODULE_PATH}.DuckPond.send_webhook", new_callable=AsyncMock)
+    @patch(f"{MODULE_PATH}.send_webhook", new_callable=AsyncMock)
     @patch(f"{MODULE_PATH}.send_attachments", new_callable=AsyncMock)
     async def test_relay_message_handles_attachment_http_error(self, send_attachments, send_webhook):
         """The `relay_message` method should handle irretrievable attachments."""
@@ -337,6 +309,7 @@ class DuckPondTests(base.LoggingTestsMixin, unittest.IsolatedAsyncioTestCase):
                 await self.cog.relay_message(message)
 
             send_webhook.assert_called_once_with(
+                webhook=self.cog.webhook,
                 content=message.clean_content,
                 username=message.author.display_name,
                 avatar_url=message.author.avatar_url
diff --git a/tests/bot/cogs/test_logging.py b/tests/bot/cogs/test_logging.py
new file mode 100644
index 000000000..8a18fdcd6
--- /dev/null
+++ b/tests/bot/cogs/test_logging.py
@@ -0,0 +1,32 @@
+import unittest
+from unittest.mock import patch
+
+from bot import constants
+from bot.cogs.logging import Logging
+from tests.helpers import MockBot, MockTextChannel
+
+
+class LoggingTests(unittest.IsolatedAsyncioTestCase):
+    """Test cases for connected login."""
+
+    def setUp(self):
+        self.bot = MockBot()
+        self.cog = Logging(self.bot)
+        self.dev_log = MockTextChannel(id=1234, name="dev-log")
+
+    @patch("bot.cogs.logging.DEBUG_MODE", False)
+    async def test_debug_mode_false(self):
+        """Should send connected message to dev-log."""
+        self.bot.get_channel.return_value = self.dev_log
+
+        await self.cog.startup_greeting()
+        self.bot.wait_until_guild_available.assert_awaited_once_with()
+        self.bot.get_channel.assert_called_once_with(constants.Channels.dev_log)
+        self.dev_log.send.assert_awaited_once()
+
+    @patch("bot.cogs.logging.DEBUG_MODE", True)
+    async def test_debug_mode_true(self):
+        """Should not send anything to dev-log."""
+        await self.cog.startup_greeting()
+        self.bot.wait_until_guild_available.assert_awaited_once_with()
+        self.bot.get_channel.assert_not_called()
diff --git a/tests/bot/cogs/test_slowmode.py b/tests/bot/cogs/test_slowmode.py
new file mode 100644
index 000000000..f442814c8
--- /dev/null
+++ b/tests/bot/cogs/test_slowmode.py
@@ -0,0 +1,111 @@
+import unittest
+from unittest import mock
+
+from dateutil.relativedelta import relativedelta
+
+from bot.cogs.moderation.slowmode import Slowmode
+from bot.constants import Emojis
+from tests.helpers import MockBot, MockContext, MockTextChannel
+
+
+class SlowmodeTests(unittest.IsolatedAsyncioTestCase):
+
+    def setUp(self) -> None:
+        self.bot = MockBot()
+        self.cog = Slowmode(self.bot)
+        self.ctx = MockContext()
+
+    async def test_get_slowmode_no_channel(self) -> None:
+        """Get slowmode without a given channel."""
+        self.ctx.channel = MockTextChannel(name='python-general', slowmode_delay=5)
+
+        await self.cog.get_slowmode(self.cog, self.ctx, None)
+        self.ctx.send.assert_called_once_with("The slowmode delay for #python-general is 5 seconds.")
+
+    async def test_get_slowmode_with_channel(self) -> None:
+        """Get slowmode with a given channel."""
+        text_channel = MockTextChannel(name='python-language', slowmode_delay=2)
+
+        await self.cog.get_slowmode(self.cog, self.ctx, text_channel)
+        self.ctx.send.assert_called_once_with('The slowmode delay for #python-language is 2 seconds.')
+
+    async def test_set_slowmode_no_channel(self) -> None:
+        """Set slowmode without a given channel."""
+        test_cases = (
+            ('helpers', 23, True, f'{Emojis.check_mark} The slowmode delay for #helpers is now 23 seconds.'),
+            ('mods', 76526, False, f'{Emojis.cross_mark} The slowmode delay must be between 0 and 6 hours.'),
+            ('admins', 97, True, f'{Emojis.check_mark} The slowmode delay for #admins is now 1 minute and 37 seconds.')
+        )
+
+        for channel_name, seconds, edited, result_msg in test_cases:
+            with self.subTest(
+                channel_mention=channel_name,
+                seconds=seconds,
+                edited=edited,
+                result_msg=result_msg
+            ):
+                self.ctx.channel = MockTextChannel(name=channel_name)
+
+                await self.cog.set_slowmode(self.cog, self.ctx, None, relativedelta(seconds=seconds))
+
+                if edited:
+                    self.ctx.channel.edit.assert_awaited_once_with(slowmode_delay=float(seconds))
+                else:
+                    self.ctx.channel.edit.assert_not_called()
+
+                self.ctx.send.assert_called_once_with(result_msg)
+
+            self.ctx.reset_mock()
+
+    async def test_set_slowmode_with_channel(self) -> None:
+        """Set slowmode with a given channel."""
+        test_cases = (
+            ('bot-commands', 12, True, f'{Emojis.check_mark} The slowmode delay for #bot-commands is now 12 seconds.'),
+            ('mod-spam', 21, True, f'{Emojis.check_mark} The slowmode delay for #mod-spam is now 21 seconds.'),
+            ('admin-spam', 4323598, False, f'{Emojis.cross_mark} The slowmode delay must be between 0 and 6 hours.')
+        )
+
+        for channel_name, seconds, edited, result_msg in test_cases:
+            with self.subTest(
+                channel_mention=channel_name,
+                seconds=seconds,
+                edited=edited,
+                result_msg=result_msg
+            ):
+                text_channel = MockTextChannel(name=channel_name)
+
+                await self.cog.set_slowmode(self.cog, self.ctx, text_channel, relativedelta(seconds=seconds))
+
+                if edited:
+                    text_channel.edit.assert_awaited_once_with(slowmode_delay=float(seconds))
+                else:
+                    text_channel.edit.assert_not_called()
+
+                self.ctx.send.assert_called_once_with(result_msg)
+
+            self.ctx.reset_mock()
+
+    async def test_reset_slowmode_no_channel(self) -> None:
+        """Reset slowmode without a given channel."""
+        self.ctx.channel = MockTextChannel(name='careers', slowmode_delay=6)
+
+        await self.cog.reset_slowmode(self.cog, self.ctx, None)
+        self.ctx.send.assert_called_once_with(
+            f'{Emojis.check_mark} The slowmode delay for #careers has been reset to 0 seconds.'
+        )
+
+    async def test_reset_slowmode_with_channel(self) -> None:
+        """Reset slowmode with a given channel."""
+        text_channel = MockTextChannel(name='meta', slowmode_delay=1)
+
+        await self.cog.reset_slowmode(self.cog, self.ctx, text_channel)
+        self.ctx.send.assert_called_once_with(
+            f'{Emojis.check_mark} The slowmode delay for #meta has been reset to 0 seconds.'
+        )
+
+    @mock.patch("bot.cogs.moderation.slowmode.with_role_check")
+    @mock.patch("bot.cogs.moderation.slowmode.MODERATION_ROLES", new=(1, 2, 3))
+    def test_cog_check(self, role_check):
+        """Role check is called with `MODERATION_ROLES`"""
+        self.cog.cog_check(self.ctx)
+        role_check.assert_called_once_with(self.ctx, *(1, 2, 3))
diff --git a/tests/bot/cogs/test_snekbox.py b/tests/bot/cogs/test_snekbox.py
index cf9adbee0..343e37db9 100644
--- a/tests/bot/cogs/test_snekbox.py
+++ b/tests/bot/cogs/test_snekbox.py
@@ -233,9 +233,13 @@ class SnekboxTests(unittest.IsolatedAsyncioTestCase):
         self.cog.get_status_emoji = MagicMock(return_value=':yay!:')
         self.cog.format_output = AsyncMock(return_value=('[No output]', None))
 
+        mocked_filter_cog = MagicMock()
+        mocked_filter_cog.filter_eval = AsyncMock(return_value=False)
+        self.bot.get_cog.return_value = mocked_filter_cog
+
         await self.cog.send_eval(ctx, 'MyAwesomeCode')
         ctx.send.assert_called_once_with(
-            '@LemonLemonishBeard#0042 :yay!: Return code 0.\n\n```py\n[No output]\n```'
+            '@LemonLemonishBeard#0042 :yay!: Return code 0.\n\n```\n[No output]\n```'
         )
         self.cog.post_eval.assert_called_once_with('MyAwesomeCode')
         self.cog.get_status_emoji.assert_called_once_with({'stdout': '', 'returncode': 0})
@@ -254,10 +258,14 @@ class SnekboxTests(unittest.IsolatedAsyncioTestCase):
         self.cog.get_status_emoji = MagicMock(return_value=':yay!:')
         self.cog.format_output = AsyncMock(return_value=('Way too long beard', 'lookatmybeard.com'))
 
+        mocked_filter_cog = MagicMock()
+        mocked_filter_cog.filter_eval = AsyncMock(return_value=False)
+        self.bot.get_cog.return_value = mocked_filter_cog
+
         await self.cog.send_eval(ctx, 'MyAwesomeCode')
         ctx.send.assert_called_once_with(
             '@LemonLemonishBeard#0042 :yay!: Return code 0.'
-            '\n\n```py\nWay too long beard\n```\nFull output: lookatmybeard.com'
+            '\n\n```\nWay too long beard\n```\nFull output: lookatmybeard.com'
         )
         self.cog.post_eval.assert_called_once_with('MyAwesomeCode')
         self.cog.get_status_emoji.assert_called_once_with({'stdout': 'Way too long beard', 'returncode': 0})
@@ -275,9 +283,13 @@ class SnekboxTests(unittest.IsolatedAsyncioTestCase):
         self.cog.get_status_emoji = MagicMock(return_value=':nope!:')
         self.cog.format_output = AsyncMock()  # This function isn't called
 
+        mocked_filter_cog = MagicMock()
+        mocked_filter_cog.filter_eval = AsyncMock(return_value=False)
+        self.bot.get_cog.return_value = mocked_filter_cog
+
         await self.cog.send_eval(ctx, 'MyAwesomeCode')
         ctx.send.assert_called_once_with(
-            '@LemonLemonishBeard#0042 :nope!: Return code 127.\n\n```py\nBeard got stuck in the eval\n```'
+            '@LemonLemonishBeard#0042 :nope!: Return code 127.\n\n```\nBeard got stuck in the eval\n```'
         )
         self.cog.post_eval.assert_called_once_with('MyAwesomeCode')
         self.cog.get_status_emoji.assert_called_once_with({'stdout': 'ERROR', 'returncode': 127})
diff --git a/tests/bot/cogs/test_token_remover.py b/tests/bot/cogs/test_token_remover.py
index 33d1ec170..3349caa73 100644
--- a/tests/bot/cogs/test_token_remover.py
+++ b/tests/bot/cogs/test_token_remover.py
@@ -1,56 +1,89 @@
-import asyncio
-import logging
 import unittest
-from unittest.mock import AsyncMock, MagicMock
+from re import Match
+from unittest import mock
+from unittest.mock import MagicMock
 
-from discord import Colour
+from discord import Colour, NotFound
 
-from bot.cogs.token_remover import (
-    DELETION_MESSAGE_TEMPLATE,
-    TokenRemover,
-    setup as setup_cog,
-)
-from bot.constants import Channels, Colours, Event, Icons
-from tests.helpers import MockBot, MockMessage
+from bot import constants
+from bot.cogs import token_remover
+from bot.cogs.moderation import ModLog
+from bot.cogs.token_remover import Token, TokenRemover
+from tests.helpers import MockBot, MockMessage, autospec
 
 
-class TokenRemoverTests(unittest.TestCase):
+class TokenRemoverTests(unittest.IsolatedAsyncioTestCase):
     """Tests the `TokenRemover` cog."""
 
     def setUp(self):
         """Adds the cog, a bot, and a message to the instance for usage in tests."""
         self.bot = MockBot()
-        self.bot.get_cog.return_value = MagicMock()
-        self.bot.get_cog.return_value.send_log_message = AsyncMock()
         self.cog = TokenRemover(bot=self.bot)
 
-        self.msg = MockMessage(id=555, content='')
-        self.msg.author.__str__ = MagicMock()
-        self.msg.author.__str__.return_value = 'lemon'
-        self.msg.author.bot = False
-        self.msg.author.avatar_url_as.return_value = 'picture-lemon.png'
-        self.msg.author.id = 42
-        self.msg.author.mention = '@lemon'
+        self.msg = MockMessage(id=555, content="hello world")
         self.msg.channel.mention = "#lemonade-stand"
+        self.msg.author.__str__ = MagicMock(return_value=self.msg.author.name)
+        self.msg.author.avatar_url_as.return_value = "picture-lemon.png"
 
-    def test_is_valid_user_id_is_true_for_numeric_content(self):
-        """A string decoding to numeric characters is a valid user ID."""
-        # MTIz = base64(123)
-        self.assertTrue(TokenRemover.is_valid_user_id('MTIz'))
+    def test_is_valid_user_id_valid(self):
+        """Should consider user IDs valid if they decode entirely to ASCII digits."""
+        ids = (
+            "NDcyMjY1OTQzMDYyNDEzMzMy",
+            "NDc1MDczNjI5Mzk5NTQ3OTA0",
+            "NDY3MjIzMjMwNjUwNzc3NjQx",
+        )
+
+        for user_id in ids:
+            with self.subTest(user_id=user_id):
+                result = TokenRemover.is_valid_user_id(user_id)
+                self.assertTrue(result)
 
-    def test_is_valid_user_id_is_false_for_alphabetic_content(self):
-        """A string decoding to alphabetic characters is not a valid user ID."""
-        # YWJj = base64(abc)
-        self.assertFalse(TokenRemover.is_valid_user_id('YWJj'))
+    def test_is_valid_user_id_invalid(self):
+        """Should consider non-digit and non-ASCII IDs invalid."""
+        ids = (
+            ("SGVsbG8gd29ybGQ", "non-digit ASCII"),
+            ("0J_RgNC40LLQtdGCINC80LjRgA", "cyrillic text"),
+            ("4pO14p6L4p6C4pG34p264pGl8J-EiOKSj-KCieKBsA", "Unicode digits"),
+            ("4oaA4oaB4oWh4oWi4Lyz4Lyq4Lyr4LG9", "Unicode numerals"),
+            ("8J2fjvCdn5nwnZ-k8J2fr_Cdn7rgravvvJngr6c", "Unicode decimals"),
+            ("{hello}[world]&(bye!)", "ASCII invalid Base64"),
+            ("Þíß-ï§-ňøẗ-våłìÐ", "Unicode invalid Base64"),
+        )
 
-    def test_is_valid_timestamp_is_true_for_valid_timestamps(self):
-        """A string decoding to a valid timestamp should be recognized as such."""
-        self.assertTrue(TokenRemover.is_valid_timestamp('DN9r_A'))
+        for user_id, msg in ids:
+            with self.subTest(msg=msg):
+                result = TokenRemover.is_valid_user_id(user_id)
+                self.assertFalse(result)
 
-    def test_is_valid_timestamp_is_false_for_invalid_values(self):
-        """A string not decoding to a valid timestamp should not be recognized as such."""
-        # MTIz = base64(123)
-        self.assertFalse(TokenRemover.is_valid_timestamp('MTIz'))
+    def test_is_valid_timestamp_valid(self):
+        """Should consider timestamps valid if they're greater than the Discord epoch."""
+        timestamps = (
+            "XsyRkw",
+            "Xrim9Q",
+            "XsyR-w",
+            "XsySD_",
+            "Dn9r_A",
+        )
+
+        for timestamp in timestamps:
+            with self.subTest(timestamp=timestamp):
+                result = TokenRemover.is_valid_timestamp(timestamp)
+                self.assertTrue(result)
+
+    def test_is_valid_timestamp_invalid(self):
+        """Should consider timestamps invalid if they're before Discord epoch or can't be parsed."""
+        timestamps = (
+            ("B4Yffw", "DISCORD_EPOCH - TOKEN_EPOCH - 1"),
+            ("ew", "123"),
+            ("AoIKgA", "42076800"),
+            ("{hello}[world]&(bye!)", "ASCII invalid Base64"),
+            ("Þíß-ï§-ňøẗ-våłìÐ", "Unicode invalid Base64"),
+        )
+
+        for timestamp, msg in timestamps:
+            with self.subTest(msg=msg):
+                result = TokenRemover.is_valid_timestamp(timestamp)
+                self.assertFalse(result)
 
     def test_mod_log_property(self):
         """The `mod_log` property should ask the bot to return the `ModLog` cog."""
@@ -58,74 +91,220 @@ class TokenRemoverTests(unittest.TestCase):
         self.assertEqual(self.cog.mod_log, self.bot.get_cog.return_value)
         self.bot.get_cog.assert_called_once_with('ModLog')
 
-    def test_ignores_bot_messages(self):
-        """When the message event handler is called with a bot message, nothing is done."""
-        self.msg.author.bot = True
-        coroutine = self.cog.on_message(self.msg)
-        self.assertIsNone(asyncio.run(coroutine))
-
-    def test_ignores_messages_without_tokens(self):
-        """Messages without anything looking like a token are ignored."""
-        for content in ('', 'lemon wins'):
-            with self.subTest(content=content):
-                self.msg.content = content
-                coroutine = self.cog.on_message(self.msg)
-                self.assertIsNone(asyncio.run(coroutine))
-
-    def test_ignores_messages_with_invalid_tokens(self):
-        """Messages with values that are invalid tokens are ignored."""
-        for content in ('foo.bar.baz', 'x.y.'):
-            with self.subTest(content=content):
-                self.msg.content = content
-                coroutine = self.cog.on_message(self.msg)
-                self.assertIsNone(asyncio.run(coroutine))
-
-    def test_censors_valid_tokens(self):
-        """Valid tokens are censored."""
-        cases = (
-            # (content, censored_token)
-            ('MTIz.DN9R_A.xyz', 'MTIz.DN9R_A.xxx'),
+    async def test_on_message_edit_uses_on_message(self):
+        """The edit listener should delegate handling of the message to the normal listener."""
+        self.cog.on_message = mock.create_autospec(self.cog.on_message, spec_set=True)
+
+        await self.cog.on_message_edit(MockMessage(), self.msg)
+        self.cog.on_message.assert_awaited_once_with(self.msg)
+
+    @autospec(TokenRemover, "find_token_in_message", "take_action")
+    async def test_on_message_takes_action(self, find_token_in_message, take_action):
+        """Should take action if a valid token is found when a message is sent."""
+        cog = TokenRemover(self.bot)
+        found_token = "foobar"
+        find_token_in_message.return_value = found_token
+
+        await cog.on_message(self.msg)
+
+        find_token_in_message.assert_called_once_with(self.msg)
+        take_action.assert_awaited_once_with(cog, self.msg, found_token)
+
+    @autospec(TokenRemover, "find_token_in_message", "take_action")
+    async def test_on_message_skips_missing_token(self, find_token_in_message, take_action):
+        """Shouldn't take action if a valid token isn't found when a message is sent."""
+        cog = TokenRemover(self.bot)
+        find_token_in_message.return_value = False
+
+        await cog.on_message(self.msg)
+
+        find_token_in_message.assert_called_once_with(self.msg)
+        take_action.assert_not_awaited()
+
+    @autospec(TokenRemover, "find_token_in_message")
+    async def test_on_message_ignores_dms_bots(self, find_token_in_message):
+        """Shouldn't parse a message if it is a DM or authored by a bot."""
+        cog = TokenRemover(self.bot)
+        dm_msg = MockMessage(guild=None)
+        bot_msg = MockMessage(author=MagicMock(bot=True))
+
+        for msg in (dm_msg, bot_msg):
+            await cog.on_message(msg)
+            find_token_in_message.assert_not_called()
+
+    @autospec("bot.cogs.token_remover", "TOKEN_RE")
+    def test_find_token_no_matches(self, token_re):
+        """None should be returned if the regex matches no tokens in a message."""
+        token_re.finditer.return_value = ()
+
+        return_value = TokenRemover.find_token_in_message(self.msg)
+
+        self.assertIsNone(return_value)
+        token_re.finditer.assert_called_once_with(self.msg.content)
+
+    @autospec(TokenRemover, "is_valid_user_id", "is_valid_timestamp")
+    @autospec("bot.cogs.token_remover", "Token")
+    @autospec("bot.cogs.token_remover", "TOKEN_RE")
+    def test_find_token_valid_match(self, token_re, token_cls, is_valid_id, is_valid_timestamp):
+        """The first match with a valid user ID and timestamp should be returned as a `Token`."""
+        matches = [
+            mock.create_autospec(Match, spec_set=True, instance=True),
+            mock.create_autospec(Match, spec_set=True, instance=True),
+        ]
+        tokens = [
+            mock.create_autospec(Token, spec_set=True, instance=True),
+            mock.create_autospec(Token, spec_set=True, instance=True),
+        ]
+
+        token_re.finditer.return_value = matches
+        token_cls.side_effect = tokens
+        is_valid_id.side_effect = (False, True)  # The 1st match will be invalid, 2nd one valid.
+        is_valid_timestamp.return_value = True
+
+        return_value = TokenRemover.find_token_in_message(self.msg)
+
+        self.assertEqual(tokens[1], return_value)
+        token_re.finditer.assert_called_once_with(self.msg.content)
+
+    @autospec(TokenRemover, "is_valid_user_id", "is_valid_timestamp")
+    @autospec("bot.cogs.token_remover", "Token")
+    @autospec("bot.cogs.token_remover", "TOKEN_RE")
+    def test_find_token_invalid_matches(self, token_re, token_cls, is_valid_id, is_valid_timestamp):
+        """None should be returned if no matches have valid user IDs or timestamps."""
+        token_re.finditer.return_value = [mock.create_autospec(Match, spec_set=True, instance=True)]
+        token_cls.return_value = mock.create_autospec(Token, spec_set=True, instance=True)
+        is_valid_id.return_value = False
+        is_valid_timestamp.return_value = False
+
+        return_value = TokenRemover.find_token_in_message(self.msg)
+
+        self.assertIsNone(return_value)
+        token_re.finditer.assert_called_once_with(self.msg.content)
+
+    def test_regex_invalid_tokens(self):
+        """Messages without anything looking like a token are not matched."""
+        tokens = (
+            "",
+            "lemon wins",
+            "..",
+            "x.y",
+            "x.y.",
+            ".y.z",
+            ".y.",
+            "..z",
+            "x..z",
+            " . . ",
+            "\n.\n.\n",
+            "hellö.world.bye",
+            "base64.nötbåse64.morebase64",
+            "19jd3J.dfkm3d.€víł§tüff",
+        )
+
+        for token in tokens:
+            with self.subTest(token=token):
+                results = token_remover.TOKEN_RE.findall(token)
+                self.assertEqual(len(results), 0)
+
+    def test_regex_valid_tokens(self):
+        """Messages that look like tokens should be matched."""
+        # Don't worry, these tokens have been invalidated.
+        tokens = (
+            "NDcyMjY1OTQzMDYy_DEzMz-y.XsyRkw.VXmErH7j511turNpfURmb0rVNm8",
+            "NDcyMjY1OTQzMDYyNDEzMzMy.Xrim9Q.Ysnu2wacjaKs7qnoo46S8Dm2us8",
+            "NDc1MDczNjI5Mzk5NTQ3OTA0.XsyR-w.sJf6omBPORBPju3WJEIAcwW9Zds",
+            "NDY3MjIzMjMwNjUwNzc3NjQx.XsySD_.s45jqDV_Iisn-symw0yDRrk_jf4",
+        )
+
+        for token in tokens:
+            with self.subTest(token=token):
+                results = token_remover.TOKEN_RE.fullmatch(token)
+                self.assertIsNotNone(results, f"{token} was not matched by the regex")
+
+    def test_regex_matches_multiple_valid(self):
+        """Should support multiple matches in the middle of a string."""
+        token_1 = "NDY3MjIzMjMwNjUwNzc3NjQx.XsyWGg.uFNEQPCc4ePwGh7egG8UicQssz8"
+        token_2 = "NDcyMjY1OTQzMDYyNDEzMzMy.XsyWMw.l8XPnDqb0lp-EiQ2g_0xVFT1pyc"
+        message = f"garbage {token_1} hello {token_2} world"
+
+        results = token_remover.TOKEN_RE.finditer(message)
+        results = [match[0] for match in results]
+        self.assertCountEqual((token_1, token_2), results)
+
+    @autospec("bot.cogs.token_remover", "LOG_MESSAGE")
+    def test_format_log_message(self, log_message):
+        """Should correctly format the log message with info from the message and token."""
+        token = Token("NDY3MjIzMjMwNjUwNzc3NjQx", "XsySD_", "s45jqDV_Iisn-symw0yDRrk_jf4")
+        log_message.format.return_value = "Howdy"
+
+        return_value = TokenRemover.format_log_message(self.msg, token)
+
+        self.assertEqual(return_value, log_message.format.return_value)
+        log_message.format.assert_called_once_with(
+            author=self.msg.author,
+            author_id=self.msg.author.id,
+            channel=self.msg.channel.mention,
+            user_id=token.user_id,
+            timestamp=token.timestamp,
+            hmac="x" * len(token.hmac),
+        )
+
+    @mock.patch.object(TokenRemover, "mod_log", new_callable=mock.PropertyMock)
+    @autospec("bot.cogs.token_remover", "log")
+    @autospec(TokenRemover, "format_log_message")
+    async def test_take_action(self, format_log_message, logger, mod_log_property):
+        """Should delete the message and send a mod log."""
+        cog = TokenRemover(self.bot)
+        mod_log = mock.create_autospec(ModLog, spec_set=True, instance=True)
+        token = mock.create_autospec(Token, spec_set=True, instance=True)
+        log_msg = "testing123"
+
+        mod_log_property.return_value = mod_log
+        format_log_message.return_value = log_msg
+
+        await cog.take_action(self.msg, token)
+
+        self.msg.delete.assert_called_once_with()
+        self.msg.channel.send.assert_called_once_with(
+            token_remover.DELETION_MESSAGE_TEMPLATE.format(mention=self.msg.author.mention)
+        )
+
+        format_log_message.assert_called_once_with(self.msg, token)
+        logger.debug.assert_called_with(log_msg)
+        self.bot.stats.incr.assert_called_once_with("tokens.removed_tokens")
+
+        mod_log.ignore.assert_called_once_with(constants.Event.message_delete, self.msg.id)
+        mod_log.send_log_message.assert_called_once_with(
+            icon_url=constants.Icons.token_removed,
+            colour=Colour(constants.Colours.soft_red),
+            title="Token removed!",
+            text=log_msg,
+            thumbnail=self.msg.author.avatar_url_as.return_value,
+            channel_id=constants.Channels.mod_alerts
         )
 
-        for content, censored_token in cases:
-            with self.subTest(content=content, censored_token=censored_token):
-                self.msg.content = content
-                coroutine = self.cog.on_message(self.msg)
-                with self.assertLogs(logger='bot.cogs.token_remover', level=logging.DEBUG) as cm:
-                    self.assertIsNone(asyncio.run(coroutine))  # no return value
-
-                [line] = cm.output
-                log_message = (
-                    "Censored a seemingly valid token sent by "
-                    "lemon (`42`) in #lemonade-stand, "
-                    f"token was `{censored_token}`"
-                )
-                self.assertIn(log_message, line)
-
-                self.msg.delete.assert_called_once_with()
-                self.msg.channel.send.assert_called_once_with(
-                    DELETION_MESSAGE_TEMPLATE.format(mention='@lemon')
-                )
-                self.bot.get_cog.assert_called_with('ModLog')
-                self.msg.author.avatar_url_as.assert_called_once_with(static_format='png')
-
-                mod_log = self.bot.get_cog.return_value
-                mod_log.ignore.assert_called_once_with(Event.message_delete, self.msg.id)
-                mod_log.send_log_message.assert_called_once_with(
-                    icon_url=Icons.token_removed,
-                    colour=Colour(Colours.soft_red),
-                    title="Token removed!",
-                    text=log_message,
-                    thumbnail='picture-lemon.png',
-                    channel_id=Channels.mod_alerts
-                )
-
-
-class TokenRemoverSetupTests(unittest.TestCase):
-    """Tests setup of the `TokenRemover` cog."""
-
-    def test_setup(self):
-        """Setup of the extension should call add_cog."""
+    @mock.patch.object(TokenRemover, "mod_log", new_callable=mock.PropertyMock)
+    async def test_take_action_delete_failure(self, mod_log_property):
+        """Shouldn't send any messages if the token message can't be deleted."""
+        cog = TokenRemover(self.bot)
+        mod_log_property.return_value = mock.create_autospec(ModLog, spec_set=True, instance=True)
+        self.msg.delete.side_effect = NotFound(MagicMock(), MagicMock())
+
+        token = mock.create_autospec(Token, spec_set=True, instance=True)
+        await cog.take_action(self.msg, token)
+
+        self.msg.delete.assert_called_once_with()
+        self.msg.channel.send.assert_not_awaited()
+
+
+class TokenRemoverExtensionTests(unittest.TestCase):
+    """Tests for the token_remover extension."""
+
+    @autospec("bot.cogs.token_remover", "TokenRemover")
+    def test_extension_setup(self, cog):
+        """The TokenRemover cog should be added."""
         bot = MockBot()
-        setup_cog(bot)
+        token_remover.setup(bot)
+
+        cog.assert_called_once_with(bot)
         bot.add_cog.assert_called_once()
+        self.assertTrue(isinstance(bot.add_cog.call_args.args[0], TokenRemover))
diff --git a/tests/bot/test_pagination.py b/tests/bot/test_pagination.py
index 0a734b505..ce880d457 100644
--- a/tests/bot/test_pagination.py
+++ b/tests/bot/test_pagination.py
@@ -8,17 +8,42 @@ class LinePaginatorTests(TestCase):
 
     def setUp(self):
         """Create a paginator for the test method."""
-        self.paginator = pagination.LinePaginator(prefix='', suffix='', max_size=30)
-
-    def test_add_line_raises_on_too_long_lines(self):
-        """`add_line` should raise a `RuntimeError` for too long lines."""
-        message = f"Line exceeds maximum page size {self.paginator.max_size - 2}"
-        with self.assertRaises(RuntimeError, msg=message):
-            self.paginator.add_line('x' * self.paginator.max_size)
+        self.paginator = pagination.LinePaginator(prefix='', suffix='', max_size=30,
+                                                  scale_to_size=50)
 
     def test_add_line_works_on_small_lines(self):
         """`add_line` should allow small lines to be added."""
         self.paginator.add_line('x' * (self.paginator.max_size - 3))
+        # Note that the page isn't added to _pages until it's full.
+        self.assertEqual(len(self.paginator._pages), 0)
+
+    def test_add_line_works_on_long_lines(self):
+        """After additional lines after `max_size` is exceeded should go on the next page."""
+        self.paginator.add_line('x' * self.paginator.max_size)
+        self.assertEqual(len(self.paginator._pages), 0)
+
+        # Any additional lines should start a new page after `max_size` is exceeded.
+        self.paginator.add_line('x')
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_continuation(self):
+        """When `scale_to_size` is exceeded, remaining words should be split onto the next page."""
+        self.paginator.add_line('zyz ' * (self.paginator.scale_to_size//4 + 1))
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_no_continuation(self):
+        """If adding a new line to an existing page would exceed `max_size`, it should start a new
+        page rather than using continuation.
+        """
+        self.paginator.add_line('z' * (self.paginator.max_size - 3))
+        self.paginator.add_line('z')
+        self.assertEqual(len(self.paginator._pages), 1)
+
+    def test_add_line_truncates_very_long_words(self):
+        """`add_line` should truncate if a single long word exceeds `scale_to_size`."""
+        self.paginator.add_line('x' * (self.paginator.scale_to_size + 1))
+        # Note: item at index 1 is the truncated line, index 0 is prefix
+        self.assertEqual(self.paginator._current_page[1], 'x' * self.paginator.scale_to_size)
 
 
 class ImagePaginatorTests(TestCase):
diff --git a/tests/bot/utils/test_messages.py b/tests/bot/utils/test_messages.py
new file mode 100644
index 000000000..9c22c9751
--- /dev/null
+++ b/tests/bot/utils/test_messages.py
@@ -0,0 +1,27 @@
+import unittest
+
+from bot.utils import messages
+
+
+class TestMessages(unittest.TestCase):
+    """Tests for functions in the `bot.utils.messages` module."""
+
+    def test_sub_clyde(self):
+        """Uppercase E's and lowercase e's are substituted with their cyrillic counterparts."""
+        sub_e = "\u0435"
+        sub_E = "\u0415"  # noqa: N806: Uppercase E in variable name
+
+        test_cases = (
+            (None, None),
+            ("", ""),
+            ("clyde", f"clyd{sub_e}"),
+            ("CLYDE", f"CLYD{sub_E}"),
+            ("cLyDe", f"cLyD{sub_e}"),
+            ("BIGclyde", f"BIGclyd{sub_e}"),
+            ("small clydeus the unholy", f"small clyd{sub_e}us the unholy"),
+            ("BIGCLYDE, babyclyde", f"BIGCLYD{sub_E}, babyclyd{sub_e}"),
+        )
+
+        for username_in, username_out in test_cases:
+            with self.subTest(input=username_in, expected_output=username_out):
+                self.assertEqual(messages.sub_clyde(username_in), username_out)
diff --git a/tests/bot/utils/test_redis_cache.py b/tests/bot/utils/test_redis_cache.py
index 8c1a40640..a2f0fe55d 100644
--- a/tests/bot/utils/test_redis_cache.py
+++ b/tests/bot/utils/test_redis_cache.py
@@ -44,22 +44,14 @@ class RedisCacheTests(unittest.IsolatedAsyncioTestCase):
         with self.assertRaises(RuntimeError):
             await bad_cache.set("test", "me_up_deadman")
 
-    def test_namespace_collision(self):
-        """Test that we prevent colliding namespaces."""
-        bob_cache_1 = RedisCache()
-        bob_cache_1._set_namespace("BobRoss")
-        self.assertEqual(bob_cache_1._namespace, "BobRoss")
-
-        bob_cache_2 = RedisCache()
-        bob_cache_2._set_namespace("BobRoss")
-        self.assertEqual(bob_cache_2._namespace, "BobRoss_")
-
     async def test_set_get_item(self):
         """Test that users can set and get items from the RedisDict."""
         test_cases = (
             ('favorite_fruit', 'melon'),
             ('favorite_number', 86),
-            ('favorite_fraction', 86.54)
+            ('favorite_fraction', 86.54),
+            ('favorite_boolean', False),
+            ('other_boolean', True),
         )
 
         # Test that we can get and set different types.
diff --git a/tests/helpers.py b/tests/helpers.py
index faa839370..facc4e1af 100644
--- a/tests/helpers.py
+++ b/tests/helpers.py
@@ -5,7 +5,7 @@ import itertools
 import logging
 import unittest.mock
 from asyncio import AbstractEventLoop
-from typing import Iterable, Optional
+from typing import Callable, Iterable, Optional
 
 import discord
 from aiohttp import ClientSession
@@ -26,6 +26,24 @@ for logger in logging.Logger.manager.loggerDict.values():
     logger.setLevel(logging.CRITICAL)
 
 
+def autospec(target, *attributes: str, **kwargs) -> Callable:
+    """Patch multiple `attributes` of a `target` with autospecced mocks and `spec_set` as True."""
+    # Caller's kwargs should take priority and overwrite the defaults.
+    kwargs = {'spec_set': True, 'autospec': True, **kwargs}
+
+    # Import the target if it's a string.
+    # This is to support both object and string targets like patch.multiple.
+    if type(target) is str:
+        target = unittest.mock._importer(target)
+
+    def decorator(func):
+        for attribute in attributes:
+            patcher = unittest.mock.patch.object(target, attribute, **kwargs)
+            func = patcher(func)
+        return func
+    return decorator
+
+
 class HashableMixin(discord.mixins.EqualityComparable):
     """
     Mixin that provides similar hashing and equality functionality as discord.py's `Hashable` mixin.