Expanded integration coverage and enforced test categories.

pyproject.toml

@@ -30,6 +30,7 @@ dev = [
     "pytest-asyncio>=1.4.0",
     "pytest-cov>=7.1.0",
     "ruff>=0.15.16",
+    "simcord==1.0.1",
 ]
 
 [tool.uv]
@@ -59,13 +60,17 @@ mypy_path = "$MYPY_CONFIG_FILE_DIR/src"
 [tool.pytest.ini_options]
 asyncio_mode = "auto"
 asyncio_default_fixture_loop_scope = "function"
+asyncio_default_test_loop_scope = "function"
 testpaths = ["tests"]
-pythonpath = ["src"]
 addopts = [
     "--import-mode=importlib",
     "--strict-config",
     "--strict-markers",
 ]
+markers = [
+    "unit: fast, deterministic tests that do not cross real external boundaries",
+    "integration: tests that exercise real local boundaries such as SQLite, sockets, CLI wiring, Discord simulation, or service lifecycle",
+]
 xfail_strict = true
 
 [tool.ruff]
@@ -111,3 +116,4 @@ omit = [
 [tool.coverage.report]
 show_missing = true
 skip_empty = true
+fail_under = 95

tests/conftest.py

@@ -12,21 +12,36 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""Shared pytest fixtures for the test suite."""
-
-from typing import TYPE_CHECKING
+"""Shared pytest hooks for the test suite."""
 
 import pytest
 
-from crabstero.database import Database
 
-if TYPE_CHECKING:
-    from collections.abc import AsyncGenerator
+@pytest.hookimpl(tryfirst=True)
+def pytest_collection_modifyitems(
+    config: pytest.Config,
+    items: list[pytest.Item],
+) -> None:
+    """Apply and enforce primary test category markers by directory."""
+    tests_root = config.rootpath / "tests"
+    category_roots = (
+        (tests_root / "unit", pytest.mark.unit),
+        (tests_root / "integration", pytest.mark.integration),
+    )
+    uncategorized: list[str] = []
 
+    for item in items:
+        for category_root, marker in category_roots:
+            if item.path.is_relative_to(category_root):
+                item.add_marker(marker)
+                break
+        else:
+            uncategorized.append(str(item.path.relative_to(config.rootpath)))
 
-@pytest.fixture
-async def db() -> AsyncGenerator[Database]:
-    """Yield a Database backed by an in-memory SQLite database."""
-    database = await Database.connect(":memory:")
-    yield database
-    await database.close()
+    if uncategorized:
+        formatted_paths = "\n".join(f"  - {path}" for path in uncategorized)
+        msg = (
+            "Tests must live under tests/unit or tests/integration.\n"
+            f"Uncategorized tests:\n{formatted_paths}"
+        )
+        raise pytest.UsageError(msg)

tests/integration/cli/__init__.py

@@ -0,0 +1,15 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""CLI integration tests for Crabstero."""

tests/integration/cli/test_systemd_notify.py

@@ -0,0 +1,89 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Integration tests for systemd notification socket behavior."""
+
+import logging
+import os
+import socket
+import sys
+from typing import TYPE_CHECKING
+
+import pytest
+
+from crabstero.cli import _sd_notify
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+
+pytestmark = pytest.mark.skipif(
+    os.name != "posix" or not hasattr(socket, "AF_UNIX"),
+    reason="systemd notification sockets require Unix-domain socket support",
+)
+
+
+class TestSystemdNotifySocket:
+    """Systemd notification helper behavior against real Unix-domain sockets."""
+
+    def test_sd_notify_sends_datagram(
+        self,
+        tmp_path: Path,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
+        """_sd_notify sends the payload to NOTIFY_SOCKET."""
+        socket_path = tmp_path / "notify.sock"
+
+        with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as server:
+            server.bind(str(socket_path))
+            server.settimeout(1)
+            monkeypatch.setenv("NOTIFY_SOCKET", str(socket_path))
+
+            _sd_notify("READY=1")
+
+            assert server.recv(1024) == b"READY=1"
+
+    def test_sd_notify_ignores_socket_errors(
+        self,
+        tmp_path: Path,
+        monkeypatch: pytest.MonkeyPatch,
+        caplog: pytest.LogCaptureFixture,
+    ) -> None:
+        """_sd_notify logs and suppresses notification socket send failures."""
+        monkeypatch.setenv("NOTIFY_SOCKET", str(tmp_path / "missing.sock"))
+
+        with caplog.at_level(logging.DEBUG, logger="crabstero"):
+            _sd_notify("READY=1")
+
+        assert "Could not send systemd notification" in caplog.text
+
+    @pytest.mark.skipif(
+        sys.platform != "linux",
+        reason="abstract Unix sockets are Linux-specific",
+    )
+    def test_sd_notify_sends_to_abstract_socket(
+        self,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
+        """@-prefixed NOTIFY_SOCKET values target Linux abstract sockets."""
+        socket_name = f"crabstero-notify-{os.getpid()}"
+
+        with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as server:
+            server.bind(f"\0{socket_name}")
+            server.settimeout(1)
+            monkeypatch.setenv("NOTIFY_SOCKET", f"@{socket_name}")
+
+            _sd_notify("READY=1")
+
+            assert server.recv(1024) == b"READY=1"

tests/integration/database/__init__.py

@@ -0,0 +1,15 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Database integration tests for Crabstero."""

tests/integration/database/conftest.py

@@ -0,0 +1,35 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Fixtures used only by database-bound integration tests."""
+
+from typing import TYPE_CHECKING
+
+import pytest
+
+from crabstero.database import Database
+
+if TYPE_CHECKING:
+    from collections.abc import AsyncGenerator
+    from pathlib import Path
+
+
+@pytest.fixture
+async def db(tmp_path: Path) -> AsyncGenerator[Database]:
+    """Yield an isolated file-backed database for SQLite integration tests."""
+    database = await Database.connect(str(tmp_path / "crabstero.db"))
+    try:
+        yield database
+    finally:
+        await database.close()

tests/integration/database/test_database.py

@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""Unit tests for the Database class.
+"""Integration tests for the Database class.
 
 Tests cover Database.connect (pragmas, schema), markov start word and
 transition CRUD, image storage, flag CRUD, and channel ingestion tracking.
@@ -509,21 +509,21 @@ class TestTransactionRollback:
 
     async def test_error_rolls_back_insert(self, db: Database) -> None:
         """An error during a transaction prevents partial data from persisting."""
-        with pytest.raises(RuntimeError, match="simulated"):
-            await self._insert_and_fail(db)
-        assert await db.get_random_start_word(1) is None
 
-    @staticmethod
-    async def _insert_and_fail(db: Database) -> None:
-        async with db._transaction():
-            await db._connection.execute(
-                "INSERT INTO markov_start_words"
-                " (channel_id, user_id, word)"
-                " VALUES (?, ?, ?)",
-                (1, 100, "should_not_persist"),
-            )
-            msg = "simulated failure"
-            raise RuntimeError(msg)
+        async def insert_and_fail() -> None:
+            async with db._transaction():
+                await db._connection.execute(
+                    "INSERT INTO markov_start_words"
+                    " (channel_id, user_id, word)"
+                    " VALUES (?, ?, ?)",
+                    (1, 100, "should_not_persist"),
+                )
+                msg = "simulated failure"
+                raise RuntimeError(msg)
+
+        with pytest.raises(RuntimeError, match="simulated"):
+            await insert_and_fail()
+        assert await db.get_random_start_word(1) is None
 
 
 class TestForgetUser:
@@ -629,13 +629,17 @@ class TestWriteDurability:
         """Data written via add_markov_data is durable after close/reopen."""
         db_path = str(tmp_path / "durability.db")
         db = await Database.connect(db_path)
-        await db.add_markov_data(
-            [StartWord(1, 100, "Hello")],
-            [Transition(1, 100, "Hello", "world.")],
-        )
-        await db.close()
+        try:
+            await db.add_markov_data(
+                [StartWord(1, 100, "Hello")],
+                [Transition(1, 100, "Hello", "world.")],
+            )
+        finally:
+            await db.close()
 
         db2 = await Database.connect(db_path)
-        assert await db2.get_random_start_word(1) == "Hello"
-        assert await db2.get_random_next_word(1, "Hello") == "world."
-        await db2.close()
+        try:
+            assert await db2.get_random_start_word(1) == "Hello"
+            assert await db2.get_random_next_word(1, "Hello") == "world."
+        finally:
+            await db2.close()

tests/integration/database/test_ingest_uningest.py

@@ -14,8 +14,10 @@
 
 """Integration tests for the full ingest → uningest cycle."""
 
+from collections.abc import Awaitable, Callable
 from typing import TYPE_CHECKING
 
+import aiosqlite
 import pytest
 
 from crabstero.cache import CachedMessage, IngestCache
@@ -24,18 +26,31 @@ from crabstero.markov import ingest, uningest
 from crabstero.messages import uningest_message
 
 if TYPE_CHECKING:
-    import aiosqlite
-
     from crabstero.database import Database
 
+type SnapshotRows = Callable[["Database"], Awaitable[dict[str, list[aiosqlite.Row]]]]
 
-async def _snapshot(db: Database) -> dict[str, list[aiosqlite.Row]]:
-    """Return sorted rows from all Markov-related tables."""
-    tables: dict[str, list[aiosqlite.Row]] = {}
-    for table in ("markov_start_words", "markov_transitions", "channel_images"):
-        async with db._connection.execute(f"SELECT * FROM {table}") as cursor:  # noqa: S608
-            tables[table] = sorted(await cursor.fetchall())
-    return tables
+
+@pytest.fixture
+def snapshot_rows() -> SnapshotRows:
+    """Return a snapshot reader for Markov and image tables."""
+
+    async def read(db: Database) -> dict[str, list[aiosqlite.Row]]:
+        tables: dict[str, list[aiosqlite.Row]] = {}
+        for table in ("markov_start_words", "markov_transitions", "channel_images"):
+            async with db._connection.execute(
+                f"SELECT * FROM {table}",  # noqa: S608
+            ) as cursor:
+                tables[table] = sorted(await cursor.fetchall())
+        return tables
+
+    return read
+
+
+@pytest.fixture
+def ingest_cache() -> IngestCache:
+    """Return an empty ingest cache for uningest-message tests."""
+    return IngestCache()
 
 
 class TestIngestUningestCycle:
@@ -114,12 +129,17 @@ class TestUningestRestoresState:
             ),
         ],
     )
-    async def test_uningest_restores_empty_db(self, db: Database, text: str) -> None:
+    async def test_uningest_restores_empty_db(
+        self,
+        db: Database,
+        text: str,
+        snapshot_rows: SnapshotRows,
+    ) -> None:
         """Ingest then uningest on an empty database leaves all tables empty."""
-        before = await _snapshot(db)
+        before = await snapshot_rows(db)
         await ingest(db, 1, 100, text)
         await uningest(db, 1, 100, text)
-        after = await _snapshot(db)
+        after = await snapshot_rows(db)
         assert after == before
 
     @pytest.mark.parametrize(
@@ -136,26 +156,26 @@ class TestUningestRestoresState:
         self,
         db: Database,
         text: str,
+        snapshot_rows: SnapshotRows,
     ) -> None:
         """Ingest then uningest preserves unrelated pre-existing data exactly."""
         await ingest(db, 99, 200, "Pre-existing data stays safe.")
         await db.add_images([ChannelImage(99, 200, "https://example.com/existing.png")])
 
-        before = await _snapshot(db)
+        before = await snapshot_rows(db)
         await ingest(db, 1, 100, text)
         await uningest(db, 1, 100, text)
-        after = await _snapshot(db)
+        after = await snapshot_rows(db)
         assert after == before
 
 
 class TestUningestMessage:
     """Orchestrated uningest via cache lookup and database reversal."""
 
-    async def test_content_only(self, db: Database) -> None:
+    async def test_content_only(self, db: Database, ingest_cache: IngestCache) -> None:
         """Uningest reverses a content-only message via the cache."""
         await ingest(db, 1, 100, "Hello beautiful world.")
-        cache = IngestCache()
-        cache.put(
+        ingest_cache.put(
             555,
             CachedMessage(
                 channel_id=1,
@@ -166,17 +186,16 @@ class TestUningestMessage:
             ),
         )
 
-        await uningest_message(db, cache, 555)
+        await uningest_message(db, ingest_cache, 555)
 
         assert await db.get_random_start_word(1) is None
         assert await db.get_random_next_word(1, "Hello") is None
 
-    async def test_embeds_only(self, db: Database) -> None:
+    async def test_embeds_only(self, db: Database, ingest_cache: IngestCache) -> None:
         """Uningest reverses embed text ingestion."""
         await ingest(db, 1, 100, "Embed title here.")
         await ingest(db, 1, 100, "Embed description here.")
-        cache = IngestCache()
-        cache.put(
+        ingest_cache.put(
             556,
             CachedMessage(
                 channel_id=1,
@@ -187,17 +206,20 @@ class TestUningestMessage:
             ),
         )
 
-        await uningest_message(db, cache, 556)
+        await uningest_message(db, ingest_cache, 556)
 
         assert await db.get_random_start_word(1) is None
 
-    async def test_content_with_embeds_and_images(self, db: Database) -> None:
+    async def test_content_with_embeds_and_images(
+        self,
+        db: Database,
+        ingest_cache: IngestCache,
+    ) -> None:
         """Uningest reverses content, embed text, and image data together."""
         await ingest(db, 1, 100, "Body text here.")
         await ingest(db, 1, 100, "Embed title.")
         await db.add_images([ChannelImage(1, 100, "https://example.com/img.png")])
-        cache = IngestCache()
-        cache.put(
+        ingest_cache.put(
             557,
             CachedMessage(
                 channel_id=1,
@@ -208,28 +230,35 @@ class TestUningestMessage:
             ),
         )
 
-        await uningest_message(db, cache, 557)
+        await uningest_message(db, ingest_cache, 557)
 
         assert await db.get_random_start_word(1) is None
         assert await db.get_random_image(1) is None
 
-    async def test_cache_miss_is_noop(self, db: Database) -> None:
+    async def test_cache_miss_is_noop(
+        self,
+        db: Database,
+        ingest_cache: IngestCache,
+        snapshot_rows: SnapshotRows,
+    ) -> None:
         """A message not in the cache leaves the database unchanged."""
         await ingest(db, 1, 100, "Keep this data.")
-        cache = IngestCache()
-        before = await _snapshot(db)
+        before = await snapshot_rows(db)
 
-        await uningest_message(db, cache, 999)
+        await uningest_message(db, ingest_cache, 999)
 
-        after = await _snapshot(db)
+        after = await snapshot_rows(db)
         assert after == before
 
-    async def test_preserves_other_messages(self, db: Database) -> None:
+    async def test_preserves_other_messages(
+        self,
+        db: Database,
+        ingest_cache: IngestCache,
+    ) -> None:
         """Uningesting one message leaves another message's data intact."""
         await ingest(db, 1, 100, "First message.")
         await ingest(db, 1, 100, "Second message.")
-        cache = IngestCache()
-        cache.put(
+        ingest_cache.put(
             601,
             CachedMessage(
                 channel_id=1,
@@ -240,16 +269,19 @@ class TestUningestMessage:
             ),
         )
 
-        await uningest_message(db, cache, 601)
+        await uningest_message(db, ingest_cache, 601)
 
         assert await db.get_random_start_word(1) == "Second"
         assert await db.get_random_next_word(1, "Second") == "message."
 
-    async def test_pops_entry_from_cache(self, db: Database) -> None:
+    async def test_pops_entry_from_cache(
+        self,
+        db: Database,
+        ingest_cache: IngestCache,
+    ) -> None:
         """The cache entry is consumed after uningest."""
         await ingest(db, 1, 100, "Hello world.")
-        cache = IngestCache()
-        cache.put(
+        ingest_cache.put(
             602,
             CachedMessage(
                 channel_id=1,
@@ -260,6 +292,6 @@ class TestUningestMessage:
             ),
         )
 
-        await uningest_message(db, cache, 602)
+        await uningest_message(db, ingest_cache, 602)
 
-        assert cache.pop(602) is None
+        assert ingest_cache.pop(602) is None

tests/integration/discord/__init__.py

@@ -0,0 +1,15 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Discord-boundary integration tests."""

tests/integration/discord/conftest.py

@@ -0,0 +1,129 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Fixtures used only by Simcord-backed Discord integration tests."""
+
+from collections.abc import Awaitable, Callable
+from dataclasses import dataclass
+from typing import TYPE_CHECKING
+
+import pytest
+
+from crabstero.bot import Crabstero
+from crabstero.database import Database
+
+if TYPE_CHECKING:
+    from collections.abc import AsyncGenerator
+    from pathlib import Path
+
+    from simcord import ChannelHandle, Env, GuildHandle, MemberActor
+
+type StartWordsForChannel = Callable[[Database, int], Awaitable[list[str]]]
+type MakeSimcordTextChannel = Callable[["Env"], Awaitable["SimcordTextChannel"]]
+type MakeSimcordMemberChannel = Callable[["Env"], Awaitable["SimcordMemberChannel"]]
+
+
+@dataclass(frozen=True, slots=True)
+class SimcordTextChannel:
+    """Guild and text channel created inside a running Simcord environment."""
+
+    guild: GuildHandle
+    channel: ChannelHandle
+
+
+@dataclass(frozen=True, slots=True)
+class SimcordMemberChannel:
+    """Guild, text channel, and human member for Discord flow tests."""
+
+    guild: GuildHandle
+    member: MemberActor
+    channel: ChannelHandle
+
+
+@pytest.fixture
+async def crabstero_bot(tmp_path: Path) -> AsyncGenerator[Crabstero]:
+    """Yield the Crabstero bot instance inspected by Discord integration tests."""
+    bot = Crabstero(str(tmp_path / "crabstero.db"))
+    try:
+        yield bot
+    finally:
+        bot.ws = None  # type: ignore[assignment]
+        await bot.close()
+
+
+@pytest.fixture
+def simcord_bot(crabstero_bot: Crabstero) -> Crabstero:
+    """Expose Crabstero under the fixture name required by Simcord."""
+    return crabstero_bot
+
+
+@pytest.fixture
+def make_simcord_text_channel() -> MakeSimcordTextChannel:
+    """Return a factory for guild text channels in any Simcord environment."""
+
+    async def make(env: Env) -> SimcordTextChannel:
+        guild = env.create_guild()
+        await env.settle()
+        channel = guild.create_text_channel("general")
+        await env.settle()
+        return SimcordTextChannel(guild, channel)
+
+    return make
+
+
+@pytest.fixture
+async def simcord_text_channel(
+    simcord_env: Env,
+    make_simcord_text_channel: MakeSimcordTextChannel,
+) -> SimcordTextChannel:
+    """Create one guild text channel in the default Simcord environment."""
+    return await make_simcord_text_channel(simcord_env)
+
+
+@pytest.fixture
+def make_simcord_member_channel() -> MakeSimcordMemberChannel:
+    """Return a factory for guild/member/channel triples in any Simcord env."""
+
+    async def make(env: Env) -> SimcordMemberChannel:
+        guild = env.create_guild()
+        await env.settle()
+        channel = guild.create_text_channel("general")
+        member = guild.add_member(env.create_user("Ada"))
+        await env.settle()
+        return SimcordMemberChannel(guild, member, channel)
+
+    return make
+
+
+@pytest.fixture
+async def simcord_member_channel(
+    simcord_env: Env,
+    make_simcord_member_channel: MakeSimcordMemberChannel,
+) -> SimcordMemberChannel:
+    """Create one guild text channel and human member in the default Simcord env."""
+    return await make_simcord_member_channel(simcord_env)
+
+
+@pytest.fixture
+def start_words_for_channel() -> StartWordsForChannel:
+    """Return a reader for persisted Markov start words in one Discord channel."""
+
+    async def read(db: Database, channel_id: int) -> list[str]:
+        async with db._connection.execute(
+            "SELECT word FROM markov_start_words WHERE channel_id = ? ORDER BY word",
+            (channel_id,),
+        ) as cursor:
+            return [str(row[0]) for row in await cursor.fetchall()]
+
+    return read

tests/integration/discord/test_bot_lifecycle.py

@@ -0,0 +1,251 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Simcord integration tests for Crabstero bot lifecycle behavior."""
+
+from typing import TYPE_CHECKING, Any, cast
+
+import discord
+import pytest
+from discord import app_commands
+from simcord import run
+
+from crabstero import metrics
+from crabstero.bot import Crabstero, TrackedModal, TrackedView
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+    from simcord import Env
+
+    from tests.integration.discord.conftest import (
+        MakeSimcordMemberChannel,
+        SimcordMemberChannel,
+    )
+
+
+def _counter_value(counter: Any, **labels: str) -> float:
+    """Return the current value for a labelled Prometheus counter."""
+    return float(counter.labels(**labels)._value.get())
+
+
+class TestSetupHook:
+    """Bot startup wires Discord cogs and slash commands under Simcord."""
+
+    def test_db_before_setup_raises(self, tmp_path: Path) -> None:
+        """The database property is unavailable before setup_hook runs."""
+        bot = Crabstero(str(tmp_path / "not-started.db"))
+
+        with pytest.raises(RuntimeError, match="Database is not initialized"):
+            _ = bot.db
+
+    async def test_loads_cogs_and_syncs_commands(
+        self,
+        simcord_env: Env,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """setup_hook loads expected cogs and syncs app commands."""
+        assert set(crabstero_bot.cogs) == {
+            "InteractionCog",
+            "MessageCog",
+            "ServerEventsCog",
+        }
+
+        commands = simcord_env.backend.commands[None]
+        assert {name for name, _ in commands} == {"forgetme", "pingme"}
+
+        application_id = simcord_env.backend.application_id
+        http_routes = [f"{method} {path}" for method, path, _ in simcord_env.http_log]
+        assert f"GET /applications/{application_id}/commands" in http_routes
+        assert f"PUT /applications/{application_id}/commands" in http_routes
+
+    async def test_metrics_server_lifecycle_starts_and_stops(
+        self,
+        tmp_path: Path,
+    ) -> None:
+        """A configured metrics server is started and stopped with the bot."""
+        bot = Crabstero(
+            str(tmp_path / "metrics.db"),
+            metrics_address=metrics.TcpMetricsAddress("127.0.0.1", 0),
+        )
+        try:
+            async with run(bot):
+                assert bot._metrics_server is not None
+                assert bot._metrics_server.port > 0
+        finally:
+            bot.ws = None  # type: ignore[assignment]
+            await bot.close()
+
+
+class TestMetrics:
+    """Bot-level metrics are incremented by lifecycle error paths."""
+
+    def test_dispatch_increments_discord_event_metric(
+        self,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """Dispatch increments the labelled Discord event counter."""
+        event = "codex_lifecycle_metric"
+        before = _counter_value(metrics.DISCORD_EVENTS, event=event)
+
+        crabstero_bot.dispatch(event)
+
+        assert _counter_value(metrics.DISCORD_EVENTS, event=event) == before + 1
+
+    async def test_on_error_increments_event_error_metric(
+        self,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """Unhandled event listener failures are counted by event name."""
+        source = "on_message"
+        before = _counter_value(metrics.ERRORS, source=source)
+
+        await crabstero_bot.on_error(source)
+
+        assert _counter_value(metrics.ERRORS, source=source) == before + 1
+
+    async def test_tracked_view_and_modal_errors_increment_metrics(self) -> None:
+        """Tracked UI error handlers increment their error counters."""
+        view_before = _counter_value(metrics.ERRORS, source="view")
+        modal_before = _counter_value(metrics.ERRORS, source="modal")
+        interaction = cast("discord.Interaction", object())
+        button = cast("discord.ui.Item[TrackedView]", discord.ui.Button(label="Run"))
+
+        await TrackedView().on_error(interaction, RuntimeError("view failed"), button)
+        await TrackedModal(title="Tracked").on_error(
+            interaction,
+            RuntimeError("modal failed"),
+        )
+
+        assert _counter_value(metrics.ERRORS, source="view") == view_before + 1
+        assert _counter_value(metrics.ERRORS, source="modal") == modal_before + 1
+
+
+class TestCommandErrors:
+    """Unhandled app command errors produce an ephemeral fallback response."""
+
+    async def test_app_command_error_sends_ephemeral_fallback(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        monkeypatch: pytest.MonkeyPatch,
+    ) -> None:
+        """A failing slash command is captured and answered by tree.on_error."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+
+        async def raise_on_set_flag(
+            _entity_type: str,
+            _entity_id: str,
+            _flag_name: str,
+        ) -> None:
+            raise RuntimeError("database unavailable")
+
+        monkeypatch.setattr(crabstero_bot.db, "set_flag", raise_on_set_flag)
+        errors_before = _counter_value(metrics.ERRORS, source="command")
+
+        result = await member.slash(channel, "pingme")
+
+        assert result.response is not None
+        assert result.response.ephemeral is True
+        assert result.response.content == (
+            "I encountered an error while processing this command."
+            " Please try again later."
+        )
+        assert _counter_value(metrics.ERRORS, source="command") == errors_before + 1
+
+    async def test_app_command_error_mentions_developer_when_metrics_are_enabled(
+        self,
+        tmp_path: Path,
+        monkeypatch: pytest.MonkeyPatch,
+        make_simcord_member_channel: MakeSimcordMemberChannel,
+    ) -> None:
+        """Configured metrics switch command errors to the notified-developer copy."""
+        bot = Crabstero(
+            str(tmp_path / "metrics-command-errors.db"),
+            metrics_address=metrics.TcpMetricsAddress("127.0.0.1", 0),
+        )
+        try:
+            async with run(bot) as env:
+                context = await make_simcord_member_channel(env)
+                member = context.member
+                channel = context.channel
+
+                async def raise_on_set_flag(
+                    _entity_type: str,
+                    _entity_id: str,
+                    _flag_name: str,
+                ) -> None:
+                    raise RuntimeError("database unavailable")
+
+                monkeypatch.setattr(bot.db, "set_flag", raise_on_set_flag)
+                errors_before = _counter_value(metrics.ERRORS, source="command")
+
+                result = await member.slash(channel, "pingme")
+
+                assert result.response is not None
+                assert result.response.ephemeral is True
+                assert result.response.content == (
+                    "I encountered an error while processing this command."
+                    " The developer has been notified,"
+                    " please try again later."
+                )
+                assert (
+                    _counter_value(metrics.ERRORS, source="command")
+                    == errors_before + 1
+                )
+        finally:
+            bot.ws = None  # type: ignore[assignment]
+            await bot.close()
+
+    async def test_app_command_error_after_defer_sends_ephemeral_followup(
+        self,
+        tmp_path: Path,
+        make_simcord_member_channel: MakeSimcordMemberChannel,
+    ) -> None:
+        """A command that has already acknowledged uses a followup fallback."""
+        bot = Crabstero(str(tmp_path / "deferred-command-errors.db"))
+
+        @app_commands.command(
+            name="deferboom",
+            description="Fail after acknowledging the interaction.",
+        )
+        async def deferboom(interaction: discord.Interaction) -> None:
+            await interaction.response.defer(ephemeral=True)
+            raise RuntimeError("deferred command failed")
+
+        bot.tree.add_command(deferboom)
+        try:
+            async with run(bot) as env:
+                context = await make_simcord_member_channel(env)
+                errors_before = _counter_value(metrics.ERRORS, source="command")
+
+                result = await context.member.slash(context.channel, "deferboom")
+
+                assert result.deferred is True
+                assert result.response is None
+                assert len(result.followups) == 1
+                followup = result.followups[0]
+                assert followup.ephemeral is True
+                assert followup.content == (
+                    "I encountered an error while processing this command."
+                    " Please try again later."
+                )
+                assert (
+                    _counter_value(metrics.ERRORS, source="command")
+                    == errors_before + 1
+                )
+        finally:
+            bot.ws = None  # type: ignore[assignment]
+            await bot.close()

tests/integration/discord/test_interactions.py

@@ -0,0 +1,276 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Simcord integration tests for Crabstero slash commands."""
+
+from collections.abc import Awaitable, Callable
+from typing import TYPE_CHECKING
+
+import pytest
+
+from crabstero.database import ChannelImage, StartWord, Transition
+from crabstero.flags import Flag
+
+if TYPE_CHECKING:
+    from simcord import Env
+
+    from crabstero.bot import Crabstero
+    from crabstero.database import Database
+    from tests.integration.discord.conftest import SimcordMemberChannel
+
+type SeedForgetmeData = Callable[["Database", int], Awaitable[None]]
+type ForgetmeRowsForUser = Callable[["Database", int], Awaitable[tuple[int, int, int]]]
+
+
+@pytest.fixture
+def seed_forgetme_data() -> SeedForgetmeData:
+    """Return a seeder for user-owned and unrelated /forgetme database rows."""
+
+    async def seed(db: Database, user_id: int) -> None:
+        await db.add_markov_data(
+            [
+                StartWord(10, user_id, "delete"),
+                StartWord(10, 999, "keep"),
+            ],
+            [
+                Transition(10, user_id, "delete", "me."),
+                Transition(10, 999, "keep", "me."),
+            ],
+        )
+        await db.add_images(
+            [
+                ChannelImage(10, user_id, "https://example.com/delete.png"),
+                ChannelImage(10, 999, "https://example.com/keep.png"),
+            ],
+        )
+
+    return seed
+
+
+@pytest.fixture
+def forgetme_rows_for_user() -> ForgetmeRowsForUser:
+    """Return a reader for Markov/image row counts owned by one user."""
+
+    async def read(db: Database, user_id: int) -> tuple[int, int, int]:
+        async with db._connection.execute(
+            "SELECT COUNT(*) FROM markov_start_words WHERE user_id = ?",
+            (user_id,),
+        ) as cursor:
+            row = await cursor.fetchone()
+            assert row is not None
+            start_words = row[0]
+        async with db._connection.execute(
+            "SELECT COUNT(*) FROM markov_transitions WHERE user_id = ?",
+            (user_id,),
+        ) as cursor:
+            row = await cursor.fetchone()
+            assert row is not None
+            transitions = row[0]
+        async with db._connection.execute(
+            "SELECT COUNT(*) FROM channel_images WHERE user_id = ?",
+            (user_id,),
+        ) as cursor:
+            row = await cursor.fetchone()
+            assert row is not None
+            images = row[0]
+        return int(start_words), int(transitions), int(images)
+
+    return read
+
+
+class TestPingMe:
+    """The /pingme command toggles persisted user opt-in state."""
+
+    async def test_first_call_opts_in(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """The first /pingme call sets allowPings and responds ephemerally."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+
+        result = await member.slash(channel, "pingme")
+
+        assert result.response is not None
+        assert result.response.ephemeral is True
+        assert "I will now ping you" in result.response.content
+        assert await crabstero_bot.db.is_flag_set(
+            "user",
+            str(member.id),
+            Flag.ALLOW_PINGS,
+        )
+
+    async def test_second_call_opts_out(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """The second /pingme call clears allowPings and responds ephemerally."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await member.slash(channel, "pingme")
+
+        result = await member.slash(channel, "pingme")
+
+        assert result.response is not None
+        assert result.response.ephemeral is True
+        assert "I will no longer ping you" in result.response.content
+        assert not await crabstero_bot.db.is_flag_set(
+            "user",
+            str(member.id),
+            Flag.ALLOW_PINGS,
+        )
+
+
+class TestForgetMe:
+    """The /forgetme command confirms, cancels, and times out hermetically."""
+
+    async def test_initial_response_has_confirmation_buttons(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+    ) -> None:
+        """The first /forgetme response is ephemeral and asks for confirmation."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+
+        result = await member.slash(channel, "forgetme")
+
+        assert result.response is not None
+        assert result.response.ephemeral is True
+        assert "Would you like to proceed?" in result.response.content
+        labels = [
+            component["label"]
+            for row in result.response.components
+            for component in row["components"]
+        ]
+        assert labels == ["Confirm", "Cancel"]
+
+    async def test_confirm_deletes_user_data_and_sets_no_ingest(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        seed_forgetme_data: SeedForgetmeData,
+        forgetme_rows_for_user: ForgetmeRowsForUser,
+    ) -> None:
+        """Confirming /forgetme deletes user data and persists noIngest."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await seed_forgetme_data(crabstero_bot.db, member.id)
+        await crabstero_bot.db.set_flag("user", str(member.id), Flag.ALLOW_PINGS)
+        await crabstero_bot.db.set_flag("user", str(member.id), Flag.NO_REPLY)
+        prompt = (await member.slash(channel, "forgetme")).response
+        assert prompt is not None
+
+        result = await member.click(prompt, label="Confirm")
+
+        assert result.response is not None
+        assert result.response.ephemeral is True
+        assert "I have deleted your data" in result.response.content
+        assert result.response.components == []
+        assert await forgetme_rows_for_user(crabstero_bot.db, member.id) == (0, 0, 0)
+        assert await forgetme_rows_for_user(crabstero_bot.db, 999) == (1, 1, 1)
+        assert await crabstero_bot.db.is_flag_set(
+            "user",
+            str(member.id),
+            Flag.NO_INGEST,
+        )
+        assert not await crabstero_bot.db.is_flag_set(
+            "user",
+            str(member.id),
+            Flag.ALLOW_PINGS,
+        )
+        assert not await crabstero_bot.db.is_flag_set(
+            "user",
+            str(member.id),
+            Flag.NO_REPLY,
+        )
+
+    async def test_cancel_leaves_user_data_and_flags(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        seed_forgetme_data: SeedForgetmeData,
+        forgetme_rows_for_user: ForgetmeRowsForUser,
+    ) -> None:
+        """Cancelling /forgetme leaves data and user flags unchanged."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await seed_forgetme_data(crabstero_bot.db, member.id)
+        await crabstero_bot.db.set_flag("user", str(member.id), Flag.ALLOW_PINGS)
+        await crabstero_bot.db.set_flag("user", str(member.id), Flag.NO_REPLY)
+        prompt = (await member.slash(channel, "forgetme")).response
+        assert prompt is not None
+
+        result = await member.click(prompt, label="Cancel")
+
+        assert result.response is not None
+        assert result.response.ephemeral is True
+        assert result.response.content == (
+            "Action cancelled. I have not modified your data."
+        )
+        assert result.response.components == []
+        assert await forgetme_rows_for_user(crabstero_bot.db, member.id) == (1, 1, 1)
+        assert await crabstero_bot.db.is_flag_set(
+            "user",
+            str(member.id),
+            Flag.ALLOW_PINGS,
+        )
+        assert await crabstero_bot.db.is_flag_set(
+            "user",
+            str(member.id),
+            Flag.NO_REPLY,
+        )
+        assert not await crabstero_bot.db.is_flag_set(
+            "user",
+            str(member.id),
+            Flag.NO_INGEST,
+        )
+
+    async def test_already_forgotten_user_gets_terminal_response(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """A noIngest user does not get another confirmation view."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await crabstero_bot.db.set_flag("user", str(member.id), Flag.NO_INGEST)
+
+        result = await member.slash(channel, "forgetme")
+
+        assert result.response is not None
+        assert result.response.ephemeral is True
+        assert result.response.content == (
+            "I have already removed your data and I am not using your messages."
+        )
+        assert result.response.components == []
+
+    async def test_confirmation_timeout_removes_view(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+    ) -> None:
+        """The /forgetme view timeout edits the original response without sleeping."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        prompt = (await member.slash(channel, "forgetme")).response
+        assert prompt is not None
+
+        await simcord_env.advance_time(181)
+
+        assert prompt.content == (
+            "This timed out. Run `/forgetme` again if you still want to."
+        )
+        assert prompt.components == []

tests/integration/discord/test_messages.py

@@ -0,0 +1,470 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Simcord integration tests for Discord message events."""
+
+from collections.abc import Awaitable, Callable
+from typing import TYPE_CHECKING
+
+import discord
+import pytest
+from simcord import run
+
+from crabstero.bot import Crabstero
+from crabstero.database import ChannelImage, StartWord, Transition
+from crabstero.flags import EntityType, Flag
+from crabstero.messages import ingest_message, reply_to_message
+
+if TYPE_CHECKING:
+    from pathlib import Path
+
+    from simcord import Env
+
+    from crabstero.database import Database
+    from tests.integration.discord.conftest import (
+        MakeSimcordMemberChannel,
+        SimcordMemberChannel,
+        StartWordsForChannel,
+    )
+
+type SeedReply = Callable[["Database", int], Awaitable[None]]
+
+
+@pytest.fixture
+def seed_reply() -> SeedReply:
+    """Return a seeder for deterministic generated replies in one channel."""
+
+    async def seed(db: Database, channel_id: int) -> None:
+        await db.add_markov_data(
+            [StartWord(channel_id, 123, "Generated")],
+            [Transition(channel_id, 123, "Generated", "reply.")],
+        )
+
+    return seed
+
+
+class TestMessageIngestion:
+    """Normal Discord message flow populates the real database."""
+
+    async def test_normal_guild_user_message_is_ingested(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """A default guild text message adds Markov data."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+
+        await member.send(channel, "Alpha beta.")
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == ["Alpha"]
+        assert (
+            await crabstero_bot.db.get_random_next_word(channel.id, "Alpha") == "beta."
+        )
+
+    async def test_bot_messages_are_ignored(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """A bot-authored gateway message is not ingested."""
+        channel = simcord_member_channel.channel
+
+        simcord_env.backend.create_message(
+            channel.id,
+            simcord_env.backend.bot_user.id,
+            "Ignore bot.",
+        )
+        await simcord_env.settle()
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == []
+
+    async def test_dm_messages_are_ignored(
+        self,
+        simcord_env: Env,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """DM messages are outside the guild channel types Crabstero handles."""
+        user = simcord_env.create_user("Ada")
+
+        await user.send_dm("Direct message.")
+
+        assert (
+            await start_words_for_channel(
+                crabstero_bot.db,
+                user.dm_channel.id,
+            )
+            == []
+        )
+
+    async def test_thread_messages_do_not_create_separate_chain(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """Messages inside threads are not ingested under the thread channel id."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        simcord_env.backend.create_thread(channel.id, "thread", member.id)
+        await simcord_env.settle()
+        thread = channel.threads[0]
+
+        await member.send(thread, "Thread only.")
+
+        assert await start_words_for_channel(crabstero_bot.db, thread.id) == []
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == []
+
+    async def test_embed_message_text_and_image_are_ingested(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """Embed titles, descriptions, and image URLs are ingested."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+
+        simcord_env.backend.create_message(
+            channel.id,
+            member.id,
+            embeds=[
+                {
+                    "title": "Title words.",
+                    "description": "Description words.",
+                    "image": {"url": "https://example.com/embed.png"},
+                },
+            ],
+        )
+        await simcord_env.settle()
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == [
+            "Description",
+            "Title",
+        ]
+        assert (
+            await crabstero_bot.db.get_random_image(channel.id)
+            == "https://example.com/embed.png"
+        )
+
+    async def test_empty_messages_are_not_ingested(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """A message with no content or embeds is ignored."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+
+        await member.send(channel)
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == []
+
+    async def test_ingest_only_mode_ingests_without_replying(
+        self,
+        tmp_path: Path,
+        make_simcord_member_channel: MakeSimcordMemberChannel,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """An ingest-only bot still ingests eligible messages and never replies."""
+        bot = Crabstero(str(tmp_path / "ingest-only.db"), ingest_only=True)
+        try:
+            async with run(bot) as env:
+                context = await make_simcord_member_channel(env)
+                member = context.member
+                channel = context.channel
+
+                await member.send(channel, "Ingest only.")
+
+                assert await start_words_for_channel(bot.db, channel.id) == ["Ingest"]
+                assert [message.content for message in channel.history()] == [
+                    "Ingest only.",
+                ]
+        finally:
+            bot.ws = None  # type: ignore[assignment]
+            await bot.close()
+
+
+class TestReplies:
+    """Mentions produce replies through the real Discord message path."""
+
+    async def test_mentioning_bot_sends_seeded_reply(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        seed_reply: SeedReply,
+    ) -> None:
+        """A mention causes a deterministic Markov reply to be posted."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await seed_reply(crabstero_bot.db, channel.id)
+
+        await member.send(channel, f"<@{simcord_env.backend.bot_user.id}> please reply")
+
+        history = channel.history()
+        assert [message.content for message in history] == [
+            f"<@{simcord_env.backend.bot_user.id}> please reply",
+            "Generated reply.",
+        ]
+        assert history[-1].reference is not None
+        assert history[-1].author == simcord_env.bot.user
+
+    async def test_mention_reply_can_include_embed_and_image(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        monkeypatch: pytest.MonkeyPatch,
+        seed_reply: SeedReply,
+    ) -> None:
+        """The optional reply embed path uses generated text and stored images."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await seed_reply(crabstero_bot.db, channel.id)
+        await crabstero_bot.db.add_images(
+            [ChannelImage(channel.id, 123, "https://example.com/reply.png")],
+        )
+        monkeypatch.setattr("crabstero.messages.secrets.randbelow", lambda _upper: 95)
+
+        await member.send(channel, f"<@{simcord_env.backend.bot_user.id}> please reply")
+
+        reply = channel.history()[-1]
+        assert reply.content == "Generated reply."
+        assert len(reply.embeds) == 1
+        assert reply.embeds[0].title == "Generated reply."
+        assert reply.embeds[0].description == "Generated reply."
+        assert reply.embeds[0].image.url == "https://example.com/reply.png"
+
+    async def test_mention_in_thread_uses_parent_channel_chain(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        seed_reply: SeedReply,
+    ) -> None:
+        """A thread mention generates from the parent channel's Markov chain."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await seed_reply(crabstero_bot.db, channel.id)
+        simcord_env.backend.create_thread(channel.id, "thread", member.id)
+        await simcord_env.settle()
+        thread = channel.threads[0]
+
+        await member.send(thread, f"<@{simcord_env.backend.bot_user.id}> thread reply")
+
+        assert [message.content for message in thread.history()] == [
+            f"<@{simcord_env.backend.bot_user.id}> thread reply",
+            "Generated reply.",
+        ]
+
+    async def test_allow_pings_flag_allows_generated_user_mentions(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """Generated mentions are allowed for users who opted in."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        target = simcord_env.create_user("Mentioned")
+        await crabstero_bot.db.add_markov_data(
+            [StartWord(channel.id, 123, "Hello")],
+            [Transition(channel.id, 123, "Hello", f"{target.mention}.")],
+        )
+        await crabstero_bot.db.set_flag(
+            EntityType.USER,
+            str(target.id),
+            Flag.ALLOW_PINGS,
+        )
+
+        await member.send(channel, f"<@{simcord_env.backend.bot_user.id}> please reply")
+
+        assert channel.history()[-1].content == f"Hello {target.mention}."
+
+    async def test_no_reply_flag_suppresses_reply(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        seed_reply: SeedReply,
+    ) -> None:
+        """The noReply flag prevents a mention response."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await seed_reply(crabstero_bot.db, channel.id)
+        await crabstero_bot.db.set_flag(
+            EntityType.CHANNEL,
+            str(channel.id),
+            Flag.NO_REPLY,
+        )
+
+        await member.send(channel, f"<@{simcord_env.backend.bot_user.id}> please reply")
+
+        assert [message.content for message in channel.history()] == [
+            f"<@{simcord_env.backend.bot_user.id}> please reply",
+        ]
+
+    async def test_missing_send_permission_suppresses_reply(
+        self,
+        simcord_env: Env,
+        crabstero_bot: Crabstero,
+        seed_reply: SeedReply,
+    ) -> None:
+        """A bot without send_messages permission does not reply."""
+        guild = simcord_env.create_guild()
+        bot_role = guild.roles[simcord_env.backend.bot_user.name]
+        channel = guild.create_text_channel(
+            "readonly",
+            overwrites={
+                bot_role: discord.PermissionOverwrite(send_messages=False),
+            },
+        )
+        member = guild.add_member(simcord_env.create_user("Ada"))
+        await simcord_env.settle()
+        await seed_reply(crabstero_bot.db, channel.id)
+
+        await member.send(channel, f"<@{simcord_env.backend.bot_user.id}> please reply")
+
+        assert [message.content for message in channel.history()] == [
+            f"<@{simcord_env.backend.bot_user.id}> please reply",
+        ]
+
+    async def test_direct_dm_reply_is_ignored(
+        self,
+        simcord_env: Env,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """The reply helper ignores messages outside guilds."""
+        user = simcord_env.create_user("Ada")
+        message = await user.send_dm(f"<@{simcord_env.backend.bot_user.id}> hi")
+
+        await reply_to_message(crabstero_bot.db, message)
+
+        assert [message.content for message in user.dm_channel.history()] == [
+            f"<@{simcord_env.backend.bot_user.id}> hi",
+        ]
+
+
+class TestDeletes:
+    """Raw delete events reverse recent message ingestion."""
+
+    async def test_delete_reverses_recent_ingest(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """Deleting a cached message removes its Markov rows."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        message = await member.send(channel, "Delete me.")
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == [
+            "Delete",
+        ]
+
+        await member.delete(message)
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == []
+
+    async def test_bulk_delete_reverses_recent_ingests(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """Bulk-deleting cached messages removes their Markov rows."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        first = await member.send(channel, "Bulk one.")
+        second = await member.send(channel, "Bulk two.")
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == [
+            "Bulk",
+            "Bulk",
+        ]
+
+        simcord_env.backend.bulk_delete_messages(channel.id, [first.id, second.id])
+        await simcord_env.settle()
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == []
+
+
+class TestFlagSuppression:
+    """Message behavior respects persisted noIngest and noReply flags."""
+
+    async def test_no_ingest_user_flag_suppresses_ingestion(
+        self,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """The noIngest flag prevents storing a user's message."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await crabstero_bot.db.set_flag(
+            EntityType.USER,
+            str(member.id),
+            Flag.NO_INGEST,
+        )
+
+        await member.send(channel, "Do not learn.")
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == []
+
+    async def test_direct_dm_ingest_is_ignored(
+        self,
+        simcord_env: Env,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """The ingest helper ignores messages outside guilds."""
+        user = simcord_env.create_user("Ada")
+        message = await user.send_dm("Direct helper call.")
+
+        await ingest_message(crabstero_bot.db, message)
+
+        assert (
+            await start_words_for_channel(
+                crabstero_bot.db,
+                user.dm_channel.id,
+            )
+            == []
+        )
+
+    async def test_direct_bot_mention_ingest_is_ignored(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """The ingest helper ignores messages that mention the bot."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        message = await member.send(
+            channel,
+            f"<@{simcord_env.backend.bot_user.id}> do not learn",
+        )
+
+        await ingest_message(crabstero_bot.db, message)
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == []

tests/integration/discord/test_server_events.py

@@ -0,0 +1,277 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Simcord integration tests for server event ingestion triggers."""
+
+from typing import TYPE_CHECKING
+
+import discord
+import pytest
+from simcord.backend.models import Overwrite
+from simcord.enums import OverwriteType
+
+from crabstero.listeners.server_events import ServerEventsCog
+from crabstero.tasks.ingestion import ingest_channel
+
+if TYPE_CHECKING:
+    from simcord import Env
+
+    from crabstero.bot import Crabstero
+    from tests.integration.discord.conftest import (
+        SimcordMemberChannel,
+        SimcordTextChannel,
+        StartWordsForChannel,
+    )
+
+
+@pytest.fixture
+def server_events_cog(crabstero_bot: Crabstero) -> ServerEventsCog:
+    """Return the loaded server-events cog from the Simcord-backed bot."""
+    cog = crabstero_bot.get_cog("ServerEventsCog")
+    assert isinstance(cog, ServerEventsCog)
+    return cog
+
+
+class TestGuildEvents:
+    """Guild availability and joins queue local channel history ingestion."""
+
+    async def test_guild_available_queues_text_and_voice_channels(
+        self,
+        simcord_env: Env,
+        server_events_cog: ServerEventsCog,
+    ) -> None:
+        """Available guilds enqueue all textable channels."""
+        guild = simcord_env.create_guild()
+        await simcord_env.settle()
+        text = guild.create_text_channel("general")
+        voice = guild.create_voice_channel("voice")
+        await simcord_env.settle()
+        cached_guild = simcord_env.bot.get_guild(guild.id)
+        assert cached_guild is not None
+
+        await server_events_cog.on_guild_available(cached_guild)
+        await simcord_env.settle()
+
+        assert await server_events_cog.bot.db.is_channel_ingested(text.id)
+        assert await server_events_cog.bot.db.is_channel_ingested(voice.id)
+
+    async def test_guild_join_queues_ingestion_and_attempts_owner_notification(
+        self,
+        simcord_env: Env,
+        simcord_text_channel: SimcordTextChannel,
+        server_events_cog: ServerEventsCog,
+    ) -> None:
+        """Joining a guild enqueues ingestion and uses the fake owner DM path."""
+        guild = simcord_text_channel.guild
+        channel = simcord_text_channel.channel
+        cached_guild = simcord_env.bot.get_guild(guild.id)
+        assert cached_guild is not None
+
+        await server_events_cog.on_guild_join(cached_guild)
+        await simcord_env.settle()
+
+        assert await server_events_cog.bot.db.is_channel_ingested(channel.id)
+        http_routes = [f"{method} {path}" for method, path, _ in simcord_env.http_log]
+        assert "GET /oauth2/applications/@me" in http_routes
+        assert "POST /users/@me/channels" in http_routes
+        assert any(route.endswith("/messages") for route in http_routes)
+
+
+class TestPermissionUpdateEvents:
+    """Permission-changing events trigger ingestion only when relevant."""
+
+    async def test_role_update_queues_only_when_permissions_change_for_bot_role(
+        self,
+        simcord_env: Env,
+        simcord_text_channel: SimcordTextChannel,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """Role updates require changed permissions and bot membership."""
+        guild = simcord_text_channel.guild
+        channel = simcord_text_channel.channel
+        role = guild.create_role("reader", permissions=discord.Permissions.none())
+        await simcord_env.settle()
+
+        simcord_env.backend.edit_role(
+            guild.id,
+            role.id,
+            {"permissions": discord.Permissions(view_channel=True).value},
+        )
+        await simcord_env.settle()
+        assert not await crabstero_bot.db.is_channel_ingested(channel.id)
+
+        bot_role = guild.roles[simcord_env.backend.bot_user.name]
+        simcord_env.backend.edit_role(
+            guild.id,
+            bot_role.id,
+            {
+                "permissions": discord.Permissions(
+                    view_channel=True,
+                    read_message_history=True,
+                ).value,
+            },
+        )
+        await simcord_env.settle()
+
+        assert await crabstero_bot.db.is_channel_ingested(channel.id)
+
+    async def test_role_update_same_permissions_does_not_queue(
+        self,
+        simcord_env: Env,
+        simcord_text_channel: SimcordTextChannel,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """A role update without permission changes is ignored."""
+        guild = simcord_text_channel.guild
+        channel = simcord_text_channel.channel
+        role = guild.create_role(
+            "reader",
+            permissions=discord.Permissions(read_message_history=True),
+        )
+        simcord_env.backend.add_member_role(
+            guild.id,
+            simcord_env.backend.bot_user.id,
+            role.id,
+        )
+        await simcord_env.settle()
+
+        simcord_env.backend.edit_role(
+            guild.id,
+            role.id,
+            {"permissions": discord.Permissions(read_message_history=True).value},
+        )
+        await simcord_env.settle()
+
+        assert not await crabstero_bot.db.is_channel_ingested(channel.id)
+
+    async def test_channel_update_queues_only_when_overwrites_change(
+        self,
+        simcord_env: Env,
+        simcord_text_channel: SimcordTextChannel,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """Channel updates without overwrite changes do not enqueue ingestion."""
+        guild = simcord_text_channel.guild
+        channel = simcord_text_channel.channel
+
+        simcord_env.backend.edit_channel(channel.id, {"topic": "no permission change"})
+        await simcord_env.settle()
+        assert not await crabstero_bot.db.is_channel_ingested(channel.id)
+
+        simcord_env.backend.set_overwrite(
+            channel.id,
+            Overwrite(
+                target_id=guild.default_role.id,
+                type=OverwriteType.ROLE,
+                allow=discord.Permissions(read_message_history=True).value,
+                deny=0,
+            ),
+        )
+        await simcord_env.settle()
+
+        assert await crabstero_bot.db.is_channel_ingested(channel.id)
+
+
+class TestIngestionTasks:
+    """Server-triggered ingestion task behavior stays local and deterministic."""
+
+    async def test_duplicate_channel_queue_requests_share_one_task(
+        self,
+        simcord_env: Env,
+        simcord_text_channel: SimcordTextChannel,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """Queuing the same channel twice before the loop runs creates one task."""
+        channel = simcord_text_channel.channel
+        cached_channel = simcord_env.bot.get_channel(channel.id)
+        assert isinstance(cached_channel, discord.TextChannel)
+
+        crabstero_bot.queue_channel_for_ingestion(cached_channel)
+        crabstero_bot.queue_channel_for_ingestion(cached_channel)
+
+        assert list(crabstero_bot._ingestion_tasks) == [channel.id]
+        await simcord_env.settle()
+
+    async def test_channel_history_ingestion_requires_read_history_permission(
+        self,
+        simcord_env: Env,
+        crabstero_bot: Crabstero,
+    ) -> None:
+        """A channel missing read history permission is skipped."""
+        guild = simcord_env.create_guild()
+        channel = guild.create_text_channel(
+            "hidden-history",
+            overwrites={
+                guild.default_role: discord.PermissionOverwrite(
+                    read_message_history=False,
+                ),
+            },
+        )
+        await simcord_env.settle()
+        cached_channel = simcord_env.bot.get_channel(channel.id)
+        assert isinstance(cached_channel, discord.TextChannel)
+
+        await ingest_channel(cached_channel, crabstero_bot.db)
+
+        assert not await crabstero_bot.db.is_channel_ingested(channel.id)
+
+    async def test_channel_history_ingestion_reads_existing_messages(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """Bulk channel ingestion reads historical messages through Discord."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        cached_channel = simcord_env.bot.get_channel(channel.id)
+        assert isinstance(cached_channel, discord.TextChannel)
+        simcord_env.backend.create_message(
+            channel.id,
+            member.id,
+            "Historical message.",
+            broadcast=False,
+        )
+
+        await ingest_channel(cached_channel, crabstero_bot.db)
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == [
+            "Historical",
+        ]
+        assert await crabstero_bot.db.is_channel_ingested(channel.id)
+
+    async def test_already_ingested_channel_is_skipped(
+        self,
+        simcord_env: Env,
+        simcord_member_channel: SimcordMemberChannel,
+        crabstero_bot: Crabstero,
+        start_words_for_channel: StartWordsForChannel,
+    ) -> None:
+        """A channel marked ingested is not read again."""
+        member = simcord_member_channel.member
+        channel = simcord_member_channel.channel
+        await crabstero_bot.db.mark_channel_ingested(channel.id)
+        cached_channel = simcord_env.bot.get_channel(channel.id)
+        assert isinstance(cached_channel, discord.TextChannel)
+        simcord_env.backend.create_message(
+            channel.id,
+            member.id,
+            "Historical message.",
+            broadcast=False,
+        )
+
+        await ingest_channel(cached_channel, crabstero_bot.db)
+
+        assert await start_words_for_channel(crabstero_bot.db, channel.id) == []

tests/integration/metrics/__init__.py

@@ -0,0 +1,15 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Metrics integration tests for Crabstero."""

tests/integration/metrics/test_server.py

@@ -0,0 +1,196 @@
+# Copyright 2026 Logan Fick
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Integration tests for the Prometheus metrics HTTP server."""
+
+import errno
+import os
+import socket
+from dataclasses import dataclass
+from http import HTTPStatus
+from typing import TYPE_CHECKING, Literal, cast
+
+import aiohttp
+import pytest
+
+from crabstero.metrics import MetricsServer, TcpMetricsAddress, UnixMetricsAddress
+
+if TYPE_CHECKING:
+    from collections.abc import AsyncGenerator
+    from pathlib import Path
+
+
+type MetricsTransport = Literal["tcp", "unix-socket"]
+
+requires_unix_socket = pytest.mark.skipif(
+    os.name != "posix" or not hasattr(socket, "AF_UNIX"),
+    reason="Unix-socket metrics transports require Unix-domain socket support",
+)
+
+
+@dataclass(frozen=True, slots=True)
+class MetricsEndpoint:
+    """Client details for one running metrics transport."""
+
+    base_url: str
+    unix_socket_path: str | None = None
+
+    def client_session(self) -> aiohttp.ClientSession:
+        """Create an aiohttp client session for this metrics transport."""
+        connector = (
+            aiohttp.UnixConnector(path=self.unix_socket_path)
+            if self.unix_socket_path is not None
+            else None
+        )
+        return aiohttp.ClientSession(connector=connector)
+
+
+@pytest.fixture(
+    params=[
+        pytest.param("tcp", id="tcp"),
+        pytest.param("unix-socket", marks=requires_unix_socket, id="unix-socket"),
+    ],
+)
+async def metrics_endpoint(
+    request: pytest.FixtureRequest,
+    tmp_path: Path,
+) -> AsyncGenerator[MetricsEndpoint]:
+    """Start a MetricsServer on each supported transport."""
+    transport = cast("MetricsTransport", request.param)
+    match transport:
+        case "tcp":
+            server = MetricsServer(TcpMetricsAddress("127.0.0.1", 0))
+            await server.start()
+            endpoint = MetricsEndpoint(f"http://127.0.0.1:{server.port}")
+        case "unix-socket":
+            socket_path = tmp_path / "metrics.sock"
+            server = MetricsServer(UnixMetricsAddress(str(socket_path)))
+            await server.start()
+            endpoint = MetricsEndpoint(
+                "http://crabstero",
+                unix_socket_path=str(socket_path),
+            )
+
+    try:
+        yield endpoint
+    finally:
+        await server.stop()
+
+
+class TestMetricsServer:
+    """HTTP server serves Prometheus metrics on /metrics."""
+
+    @requires_unix_socket
+    def test_unix_socket_server_has_no_tcp_port(self, tmp_path: Path) -> None:
+        """Unix-socket metrics servers do not expose a TCP port."""
+        server = MetricsServer(UnixMetricsAddress(str(tmp_path / "metrics.sock")))
+
+        with pytest.raises(RuntimeError, match="does not have a TCP port"):
+            _ = server.port
+
+    async def test_serves_metrics_endpoint(
+        self,
+        metrics_endpoint: MetricsEndpoint,
+    ) -> None:
+        """GET /metrics returns 200 with metric output containing our metrics."""
+        async with (
+            metrics_endpoint.client_session() as session,
+            session.get(f"{metrics_endpoint.base_url}/metrics") as resp,
+        ):
+            assert resp.status == HTTPStatus.OK
+            body = await resp.text()
+            assert "crabstero_build_info" in body
+
+    async def test_non_metrics_path_returns_404(
+        self,
+        metrics_endpoint: MetricsEndpoint,
+    ) -> None:
+        """GET on an unknown path returns 404."""
+        async with (
+            metrics_endpoint.client_session() as session,
+            session.get(f"{metrics_endpoint.base_url}/notfound") as resp,
+        ):
+            assert resp.status == HTTPStatus.NOT_FOUND
+
+    @requires_unix_socket
+    async def test_unix_socket_mode_is_applied(self, tmp_path: Path) -> None:
+        """Configured Unix socket mode is applied after startup."""
+        socket_path = tmp_path / "metrics.sock"
+        server = MetricsServer(UnixMetricsAddress(str(socket_path), mode=0o666))
+        await server.start()
+        try:
+            assert socket_path.stat().st_mode & 0o777 == 0o666
+        finally:
+            await server.stop()
+
+    @requires_unix_socket
+    async def test_stale_unix_socket_path_is_recovered(
+        self,
+        tmp_path: Path,
+    ) -> None:
+        """Startup removes an abandoned Unix socket file left by a crash."""
+        socket_path = tmp_path / "metrics.sock"
+        with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as stale_socket:
+            stale_socket.bind(str(socket_path))
+
+        server = MetricsServer(UnixMetricsAddress(str(socket_path), mode=0o666))
+        await server.start()
+        try:
+            assert socket_path.stat().st_mode & 0o777 == 0o666
+            connector = aiohttp.UnixConnector(path=str(socket_path))
+            async with (
+                aiohttp.ClientSession(connector=connector) as session,
+                session.get("http://crabstero/metrics") as resp,
+            ):
+                assert resp.status == HTTPStatus.OK
+                body = await resp.text()
+                assert "crabstero_build_info" in body
+        finally:
+            await server.stop()
+
+    @requires_unix_socket
+    async def test_active_unix_socket_path_fails(
+        self,
+        tmp_path: Path,
+    ) -> None:
+        """Startup refuses to replace a Unix socket path that is still in use."""
+        socket_path = tmp_path / "metrics.sock"
+        with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as active_socket:
+            active_socket.bind(str(socket_path))
+            active_socket.listen(1)
+
+            server = MetricsServer(UnixMetricsAddress(str(socket_path)))
+            with pytest.raises(OSError, match="already in use") as exc_info:
+                await server.start()
+
+        assert exc_info.value.errno == errno.EADDRINUSE
+
+    @requires_unix_socket
+    async def test_non_socket_unix_path_fails(self, tmp_path: Path) -> None:
+        """Startup refuses to replace a non-socket path."""
+        socket_path = tmp_path / "metrics.sock"
+        socket_path.write_text("")
+        server = MetricsServer(UnixMetricsAddress(str(socket_path)))
+        with pytest.raises(FileExistsError):
+            await server.start()
+
+    async def test_starting_server_twice_fails(self) -> None:
+        """A running metrics server cannot be started twice."""
+        server = MetricsServer(TcpMetricsAddress("127.0.0.1", 0))
+        await server.start()
+        try:
+            with pytest.raises(RuntimeError, match="already running"):
+                await server.start()
+        finally:
+            await server.stop()

tests/unit/test_cache.py

@@ -14,39 +14,59 @@
 
 """Unit tests for the IngestCache TTL cache."""
 
-import asyncio
-import time
+import pytest
 
 from crabstero.cache import CachedMessage, IngestCache
 
 
+class _FakeClock:
+    """Mutable monotonic clock for deterministic cache expiry tests."""
+
+    def __init__(self) -> None:
+        self.now = 1000.0
+
+    def __call__(self) -> float:
+        """Return the current fake monotonic timestamp."""
+        return self.now
+
+    def advance(self, seconds: float) -> None:
+        """Move the fake clock forward by the given number of seconds."""
+        self.now += seconds
+
+
+@pytest.fixture
+def cached_message() -> CachedMessage:
+    """Return a representative cache entry for put/pop behavior tests."""
+    return CachedMessage(
+        channel_id=1,
+        user_id=100,
+        content="Hello world",
+        embed_texts=["embed title"],
+        image_urls=["https://example.com/cat.png"],
+    )
+
+
+@pytest.fixture
+def fake_clock(monkeypatch: pytest.MonkeyPatch) -> _FakeClock:
+    """Patch the cache's clock and return a controllable timestamp source."""
+    clock = _FakeClock()
+    monkeypatch.setattr("crabstero.cache.time.monotonic", clock)
+    return clock
+
+
 class TestIngestCache:
     """IngestCache put, pop, and expiry behavior."""
 
-    def test_put_and_pop(self) -> None:
+    def test_put_and_pop(self, cached_message: CachedMessage) -> None:
         """A cached message can be retrieved by message ID."""
         cache = IngestCache()
-        entry = CachedMessage(
-            channel_id=1,
-            user_id=100,
-            content="Hello world",
-            embed_texts=["embed title"],
-            image_urls=["https://example.com/cat.png"],
-        )
-        cache.put(12345, entry)
-        assert cache.pop(12345) is entry
+        cache.put(12345, cached_message)
+        assert cache.pop(12345) is cached_message
 
-    def test_pop_removes_entry(self) -> None:
+    def test_pop_removes_entry(self, cached_message: CachedMessage) -> None:
         """Popping an entry removes it from the cache."""
         cache = IngestCache()
-        entry = CachedMessage(
-            channel_id=1,
-            user_id=100,
-            content="Hello",
-            embed_texts=[],
-            image_urls=[],
-        )
-        cache.put(12345, entry)
+        cache.put(12345, cached_message)
         cache.pop(12345)
         assert cache.pop(12345) is None
 
@@ -55,64 +75,55 @@ class TestIngestCache:
         cache = IngestCache()
         assert cache.pop(99999) is None
 
-    def test_expired_entry_not_returned(self) -> None:
+    def test_expired_entry_not_returned(
+        self,
+        cached_message: CachedMessage,
+        fake_clock: _FakeClock,
+    ) -> None:
         """An expired entry is not returned by pop."""
-        cache = IngestCache(ttl_seconds=0.01)
-        entry = CachedMessage(
-            channel_id=1,
-            user_id=100,
-            content="Hello",
-            embed_texts=[],
-            image_urls=[],
-        )
-        cache.put(12345, entry)
-        time.sleep(0.02)
+        cache = IngestCache(ttl_seconds=10)
+        cache.put(12345, cached_message)
+        fake_clock.advance(11)
         assert cache.pop(12345) is None
 
-    def test_cleanup_removes_expired(self) -> None:
+    def test_cleanup_removes_expired(
+        self,
+        cached_message: CachedMessage,
+        fake_clock: _FakeClock,
+    ) -> None:
         """Cleanup evicts all expired entries."""
-        cache = IngestCache(ttl_seconds=0.01)
-        entry = CachedMessage(
-            channel_id=1,
-            user_id=100,
-            content="Hello",
-            embed_texts=[],
-            image_urls=[],
-        )
-        cache.put(1, entry)
-        cache.put(2, entry)
-        time.sleep(0.02)
+        cache = IngestCache(ttl_seconds=10)
+        cache.put(1, cached_message)
+        cache.put(2, cached_message)
+        fake_clock.advance(11)
         cache._cleanup()
         assert cache.pop(1) is None
         assert cache.pop(2) is None
 
-    def test_cleanup_keeps_unexpired(self) -> None:
+    def test_cleanup_keeps_unexpired(self, cached_message: CachedMessage) -> None:
         """Cleanup does not evict entries that are still valid."""
         cache = IngestCache(ttl_seconds=300)
-        entry = CachedMessage(
-            channel_id=1,
-            user_id=100,
-            content="Hello",
-            embed_texts=[],
-            image_urls=[],
-        )
-        cache.put(1, entry)
+        cache.put(1, cached_message)
         cache._cleanup()
-        assert cache.pop(1) is entry
+        assert cache.pop(1) is cached_message
 
     async def test_start_and_stop(self) -> None:
         """The background cleanup task can be started and stopped."""
-        cache = IngestCache(ttl_seconds=0, cleanup_interval_seconds=0.01)
-        entry = CachedMessage(
-            channel_id=1,
-            user_id=100,
-            content="Hello",
-            embed_texts=[],
-            image_urls=[],
-        )
-        cache.put(1, entry)
+        cache = IngestCache()
         cache.start()
-        await asyncio.sleep(0.05)
+        assert cache._task is not None
+
         await cache.stop()
-        # Entry should have been cleaned up by the background task.
-        assert cache.pop(1) is None
+
+        assert cache._task is None
+
+    async def test_start_is_idempotent(self) -> None:
+        """Starting an already-started cache keeps the existing cleanup task."""
+        cache = IngestCache()
+        cache.start()
+        try:
+            task = cache._task
+            cache.start()
+            assert cache._task is task
+        finally:
+            await cache.stop()

tests/unit/test_cli.py

@@ -20,7 +20,6 @@ Tests cover the CLI helpers and runtime orchestration from crabstero.cli.
 import asyncio
 import os
 import signal
-import socket
 import sys
 from typing import TYPE_CHECKING, Any, ClassVar, Self
 
@@ -43,12 +42,37 @@ if TYPE_CHECKING:
 
 
 class _FakeCrabstero:
+    """Fake bot that records CLI lifecycle calls without touching Discord.
+
+    Tests can inject callbacks during login/connect and exceptions during
+    login/close to exercise CLI shutdown ordering and propagation paths.
+    """
+
     events: ClassVar[list[object]] = []
     login_error: ClassVar[BaseException | None] = None
     login_callback: ClassVar[Callable[[], None] | None] = None
     close_error: ClassVar[BaseException | None] = None
     connect_callback: ClassVar[Callable[[], None] | None] = None
 
+    @classmethod
+    def reset(
+        cls,
+        *,
+        login_error: BaseException | None = None,
+        close_error: BaseException | None = None,
+    ) -> list[object]:
+        """Clear scenario state and return the shared lifecycle event log.
+
+        The event log is shared across fake instances so tests can assert the
+        ordering of construction, login, notifications, connect, and close.
+        """
+        cls.events = []
+        cls.login_error = login_error
+        cls.login_callback = None
+        cls.close_error = close_error
+        cls.connect_callback = None
+        return cls.events
+
     def __init__(self, **kwargs: object) -> None:
         self._closed = False
         self.events.append(("init", kwargs))
@@ -94,34 +118,68 @@ class _FakeCrabstero:
         return self._closed
 
 
-def _run_coroutine(
-    coro: Coroutine[Any, Any, signal.Signals | None],
-) -> signal.Signals | None:
-    return asyncio.run(coro)
-
-
-def _prepare_main_test(
+@pytest.fixture
+def prepared_main(
     monkeypatch: pytest.MonkeyPatch,
-    *,
-    login_error: BaseException | None = None,
-    close_error: BaseException | None = None,
-) -> list[object]:
-    _FakeCrabstero.events = []
-    _FakeCrabstero.login_error = login_error
-    _FakeCrabstero.login_callback = None
-    _FakeCrabstero.close_error = close_error
-    _FakeCrabstero.connect_callback = None
+) -> Callable[..., list[object]]:
+    """Return a factory that prepares cli.main for fake-bot lifecycle tests.
 
-    def sd_notify(state: str) -> None:
-        _FakeCrabstero.events.append(("notify", state))
+    Each factory call resets the fake bot, routes systemd notifications into
+    the event log, disables watchdog setup, and makes uvloop.run execute the
+    coroutine synchronously through asyncio.run.
+    """
 
-    monkeypatch.setattr(sys, "argv", ["crabstero", "--token", "cli-token"])
-    monkeypatch.setattr(cli, "Crabstero", _FakeCrabstero)
-    monkeypatch.setattr("crabstero.cli.uvloop.run", _run_coroutine)
-    monkeypatch.setattr(cli, "_sd_notify", sd_notify)
-    monkeypatch.setattr(cli, "_watchdog_interval", lambda: None)
+    def prepare(
+        *,
+        login_error: BaseException | None = None,
+        close_error: BaseException | None = None,
+    ) -> list[object]:
+        events = _FakeCrabstero.reset(
+            login_error=login_error,
+            close_error=close_error,
+        )
 
-    return _FakeCrabstero.events
+        def sd_notify(state: str) -> None:
+            events.append(("notify", state))
+
+        monkeypatch.setattr(sys, "argv", ["crabstero", "--token", "cli-token"])
+        monkeypatch.setattr(cli, "Crabstero", _FakeCrabstero)
+        monkeypatch.setattr("crabstero.cli.uvloop.run", asyncio.run)
+        monkeypatch.setattr(cli, "_sd_notify", sd_notify)
+        monkeypatch.setattr(cli, "_watchdog_interval", lambda: None)
+
+        return events
+
+    return prepare
+
+
+@pytest.fixture
+def signal_handlers(
+    monkeypatch: pytest.MonkeyPatch,
+) -> dict[int, Callable[[], None]]:
+    """Patch signal registration and return captured signal callbacks.
+
+    The returned mapping lets tests invoke registered SIGINT/SIGTERM handlers
+    directly and assert that cleanup removes them.
+    """
+    handlers: dict[int, Callable[[], None]] = {}
+
+    class SignalLoop:
+        """Minimal event-loop facade that stores installed signal handlers."""
+
+        def add_signal_handler(
+            self,
+            sig: int,
+            callback: Callable[..., None],
+            *args: object,
+        ) -> None:
+            handlers[sig] = lambda: callback(*args)
+
+        def remove_signal_handler(self, sig: int) -> None:
+            handlers.pop(sig, None)
+
+    monkeypatch.setattr(asyncio, "get_running_loop", SignalLoop)
+    return handlers
 
 
 class TestParseArgs:
@@ -322,23 +380,6 @@ class TestSystemdNotify:
         monkeypatch.delenv("NOTIFY_SOCKET", raising=False)
         _sd_notify("READY=1")
 
-    def test_sd_notify_sends_datagram(
-        self,
-        tmp_path: Path,
-        monkeypatch: pytest.MonkeyPatch,
-    ) -> None:
-        """_sd_notify sends the payload to NOTIFY_SOCKET."""
-        socket_path = tmp_path / "notify.sock"
-
-        with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as server:
-            server.bind(str(socket_path))
-            server.settimeout(1)
-            monkeypatch.setenv("NOTIFY_SOCKET", str(socket_path))
-
-            _sd_notify("READY=1")
-
-            assert server.recv(1024) == b"READY=1"
-
 
 class TestWatchdog:
     """Systemd watchdog helper behavior."""
@@ -426,10 +467,10 @@ class TestMainLifecycle:
 
     def test_constructs_bot_without_token(
         self,
-        monkeypatch: pytest.MonkeyPatch,
+        prepared_main: Callable[..., list[object]],
     ) -> None:
         """The CLI keeps the Discord token out of Crabstero construction."""
-        events = _prepare_main_test(monkeypatch)
+        events = prepared_main()
 
         assert cli.main() == 0
 
@@ -449,14 +490,12 @@ class TestMainLifecycle:
 
     def test_main_accepts_explicit_argv(
         self,
-        monkeypatch: pytest.MonkeyPatch,
+        prepared_main: Callable[..., list[object]],
     ) -> None:
         """main(argv) runs from explicit arguments instead of sys.argv."""
-        events = _prepare_main_test(monkeypatch)
+        events = prepared_main()
 
-        assert (
-            cli.main(["--token", "argv-token", "--database-path", "/custom.db"]) == 0
-        )
+        assert cli.main(["--token", "argv-token", "--database-path", "/custom.db"]) == 0
 
         assert events[0] == (
             "init",
@@ -470,10 +509,10 @@ class TestMainLifecycle:
 
     def test_ready_sent_after_login_before_connect(
         self,
-        monkeypatch: pytest.MonkeyPatch,
+        prepared_main: Callable[..., list[object]],
     ) -> None:
         """READY=1 is sent after login succeeds and before connect starts."""
-        events = _prepare_main_test(monkeypatch)
+        events = prepared_main()
 
         assert cli.main() == 0
 
@@ -486,10 +525,10 @@ class TestMainLifecycle:
 
     def test_stopping_sent_after_clean_connect_return(
         self,
-        monkeypatch: pytest.MonkeyPatch,
+        prepared_main: Callable[..., list[object]],
     ) -> None:
         """STOPPING=1 is sent when the CLI run exits cleanly after readiness."""
-        events = _prepare_main_test(monkeypatch)
+        events = prepared_main()
 
         assert cli.main() == 0
 
@@ -499,13 +538,10 @@ class TestMainLifecycle:
 
     def test_ready_not_sent_when_login_fails(
         self,
-        monkeypatch: pytest.MonkeyPatch,
+        prepared_main: Callable[..., list[object]],
     ) -> None:
         """A login failure exits without reporting readiness."""
-        events = _prepare_main_test(
-            monkeypatch,
-            login_error=RuntimeError("login failed"),
-        )
+        events = prepared_main(login_error=RuntimeError("login failed"))
 
         with pytest.raises(RuntimeError, match="login failed"):
             cli.main()
@@ -515,32 +551,15 @@ class TestMainLifecycle:
 
     def test_shutdown_task_exception_is_propagated(
         self,
-        monkeypatch: pytest.MonkeyPatch,
+        prepared_main: Callable[..., list[object]],
+        signal_handlers: dict[int, Callable[[], None]],
     ) -> None:
         """A completed shutdown task exception is not silently dropped."""
-        signal_handlers: dict[int, Callable[[], None]] = {}
-
-        class SignalLoop:
-            def add_signal_handler(
-                self,
-                sig: int,
-                callback: Callable[..., None],
-                *args: object,
-            ) -> None:
-                signal_handlers[sig] = lambda: callback(*args)
-
-            def remove_signal_handler(self, sig: int) -> None:
-                signal_handlers.pop(sig, None)
-
-        events = _prepare_main_test(
-            monkeypatch,
-            close_error=RuntimeError("close failed"),
-        )
+        events = prepared_main(close_error=RuntimeError("close failed"))
 
         def request_shutdown() -> None:
             signal_handlers[signal.SIGTERM]()
 
-        monkeypatch.setattr(asyncio, "get_running_loop", SignalLoop)
         _FakeCrabstero.connect_callback = request_shutdown
 
         with pytest.raises(RuntimeError, match="close failed"):
@@ -559,29 +578,15 @@ class TestMainLifecycle:
         self,
         sig: signal.Signals,
         exit_code: int,
-        monkeypatch: pytest.MonkeyPatch,
+        prepared_main: Callable[..., list[object]],
+        signal_handlers: dict[int, Callable[[], None]],
     ) -> None:
         """Signal callbacks preserve SIGINT and SIGTERM CLI exit semantics."""
-        signal_handlers: dict[int, Callable[[], None]] = {}
-
-        class SignalLoop:
-            def add_signal_handler(
-                self,
-                sig: int,
-                callback: Callable[..., None],
-                *args: object,
-            ) -> None:
-                signal_handlers[sig] = lambda: callback(*args)
-
-            def remove_signal_handler(self, sig: int) -> None:
-                signal_handlers.pop(sig, None)
-
-        events = _prepare_main_test(monkeypatch)
+        events = prepared_main()
 
         def request_shutdown() -> None:
             signal_handlers[sig]()
 
-        monkeypatch.setattr(asyncio, "get_running_loop", SignalLoop)
         _FakeCrabstero.connect_callback = request_shutdown
 
         assert cli.main() == exit_code
@@ -591,29 +596,15 @@ class TestMainLifecycle:
 
     def test_registered_signal_during_login_exits_before_ready(
         self,
-        monkeypatch: pytest.MonkeyPatch,
+        prepared_main: Callable[..., list[object]],
+        signal_handlers: dict[int, Callable[[], None]],
     ) -> None:
         """A signal during login cancels startup without reporting readiness."""
-        signal_handlers: dict[int, Callable[[], None]] = {}
-
-        class SignalLoop:
-            def add_signal_handler(
-                self,
-                sig: int,
-                callback: Callable[..., None],
-                *args: object,
-            ) -> None:
-                signal_handlers[sig] = lambda: callback(*args)
-
-            def remove_signal_handler(self, sig: int) -> None:
-                signal_handlers.pop(sig, None)
-
-        events = _prepare_main_test(monkeypatch)
+        events = prepared_main()
 
         def request_shutdown() -> None:
             signal_handlers[signal.SIGINT]()
 
-        monkeypatch.setattr(asyncio, "get_running_loop", SignalLoop)
         _FakeCrabstero.login_callback = request_shutdown
 
         assert cli.main() == 130

tests/unit/test_flags.py

@@ -15,13 +15,13 @@
 """Unit tests for the flag convenience wrappers and enums.
 
 Tests cover _entity_id, Flag and EntityType enums, and the high-level
-set_flag/clear_flag/is_flag_set wrappers from crabstero.flags.
+set_flag/clear_flag/is_flag_set wrappers from crabstero.flags without crossing
+the SQLite database boundary.
 """
 
-from typing import TYPE_CHECKING
-
 import pytest
 
+from crabstero.database import Database
 from crabstero.flags import (
     EntityType,
     Flag,
@@ -31,17 +31,49 @@ from crabstero.flags import (
     set_flag,
 )
 
-if TYPE_CHECKING:
-    from crabstero.database import Database
-
 
 class _StubSnowflake:
-    """Minimal stand-in for discord.abc.Snowflake."""
+    """Minimal stand-in for objects that expose a Discord snowflake ID."""
 
     def __init__(self, *, entity_id: int = 123456789) -> None:
         self.id = entity_id
 
 
+class _FakeFlagDatabase(Database):
+    """In-memory flag store that records wrapper calls below SQLite."""
+
+    def __init__(self) -> None:
+        self.flags: set[tuple[str, str, str]] = set()
+
+    async def set_flag(self, entity_type: str, entity_id: str, flag_name: str) -> None:
+        """Record a flag set operation."""
+        self.flags.add((entity_type, entity_id, flag_name))
+
+    async def clear_flag(
+        self,
+        entity_type: str,
+        entity_id: str,
+        flag_name: str,
+    ) -> None:
+        """Record a flag clear operation."""
+        self.flags.discard((entity_type, entity_id, flag_name))
+
+    async def is_flag_set(
+        self,
+        entity_type: str,
+        entity_id: str,
+        flag_name: str,
+    ) -> bool:
+        """Return whether a flag has been set."""
+        return (entity_type, entity_id, flag_name) in self.flags
+
+
+@pytest.fixture
+def flag_db() -> _FakeFlagDatabase:
+    """Return an isolated flag store for wrapper tests."""
+    return _FakeFlagDatabase()
+
+
 class TestEntityId:
     """Entity ID extraction from Discord objects and integers."""
 
@@ -100,17 +132,33 @@ class TestSetClearCheck:
             pytest.param(Flag.ALLOW_PINGS, id="allow-pings"),
         ],
     )
-    async def test_set_then_check(self, db: Database, flag: Flag) -> None:
+    async def test_set_then_check(self, flag_db: _FakeFlagDatabase, flag: Flag) -> None:
         """A set flag is reported as set."""
-        await set_flag(db, 1, EntityType.CHANNEL, flag)
-        assert await is_flag_set(db, 1, EntityType.CHANNEL, flag) is True
+        await set_flag(flag_db, 1, EntityType.CHANNEL, flag)
+        assert await is_flag_set(flag_db, 1, EntityType.CHANNEL, flag) is True
 
-    async def test_unset_returns_false(self, db: Database) -> None:
+    async def test_unset_returns_false(self, flag_db: _FakeFlagDatabase) -> None:
         """An unset flag is reported as not set."""
-        assert await is_flag_set(db, 1, EntityType.CHANNEL, Flag.NO_REPLY) is False
+        assert (
+            await is_flag_set(
+                flag_db,
+                1,
+                EntityType.CHANNEL,
+                Flag.NO_REPLY,
+            )
+            is False
+        )
 
-    async def test_clear_removes_flag(self, db: Database) -> None:
+    async def test_clear_removes_flag(self, flag_db: _FakeFlagDatabase) -> None:
         """A cleared flag is no longer reported as set."""
-        await set_flag(db, 1, EntityType.CHANNEL, Flag.NO_REPLY)
-        await clear_flag(db, 1, EntityType.CHANNEL, Flag.NO_REPLY)
-        assert await is_flag_set(db, 1, EntityType.CHANNEL, Flag.NO_REPLY) is False
+        await set_flag(flag_db, 1, EntityType.CHANNEL, Flag.NO_REPLY)
+        await clear_flag(flag_db, 1, EntityType.CHANNEL, Flag.NO_REPLY)
+        assert (
+            await is_flag_set(
+                flag_db,
+                1,
+                EntityType.CHANNEL,
+                Flag.NO_REPLY,
+            )
+            is False
+        )

tests/unit/test_markov.py

@@ -15,14 +15,14 @@
 """Unit tests for Markov chain ingestion and generation.
 
 Tests cover is_complete_sentence, _ingest_sentence, ingest, and generate
-from crabstero.markov.
+from crabstero.markov without crossing the SQLite database boundary.
 """
 
-from typing import TYPE_CHECKING
+import contextlib
 
 import pytest
 
-from crabstero.database import StartWord, Transition
+from crabstero.database import Database, StartWord, Transition
 from crabstero.markov import (
     DEFAULT_SENTENCE_END,
     _ingest_sentence,
@@ -33,8 +33,80 @@ from crabstero.markov import (
     uningest,
 )
 
-if TYPE_CHECKING:
-    from crabstero.database import Database
+
+class _FakeMarkovDatabase(Database):
+    """In-memory Markov store with deterministic first-row selection.
+
+    The fake preserves duplicate rows and one-row-at-a-time removal semantics
+    so ingestion and uningestion tests can stay below the SQLite boundary.
+    """
+
+    def __init__(self) -> None:
+        self.start_words: list[StartWord] = []
+        self.transitions: list[Transition] = []
+
+    async def add_markov_data(
+        self,
+        start_words: list[StartWord],
+        transitions: list[Transition],
+    ) -> None:
+        """Record Markov rows exactly as the application would write them."""
+        self.start_words.extend(start_words)
+        self.transitions.extend(transitions)
+
+    async def remove_markov_data(
+        self,
+        start_words: list[StartWord],
+        transitions: list[Transition],
+    ) -> None:
+        """Remove at most one matching row per requested Markov row."""
+        for start_word in start_words:
+            with contextlib.suppress(ValueError):
+                self.start_words.remove(start_word)
+        for transition in transitions:
+            with contextlib.suppress(ValueError):
+                self.transitions.remove(transition)
+
+    async def get_random_start_word(self, channel_id: int) -> str | None:
+        """Return the first start word for deterministic generation tests."""
+        return next(
+            (row.word for row in self.start_words if row.channel_id == channel_id),
+            None,
+        )
+
+    async def get_random_next_word(self, channel_id: int, word: str) -> str | None:
+        """Return the first matching transition for deterministic tests."""
+        return next(
+            (
+                row.next_word
+                for row in self.transitions
+                if row.channel_id == channel_id and row.word == word
+            ),
+            None,
+        )
+
+    async def get_random_completing_next_word(
+        self,
+        channel_id: int,
+        word: str,
+    ) -> str | None:
+        """Return the first sentence-ending transition for deterministic tests."""
+        return next(
+            (
+                row.next_word
+                for row in self.transitions
+                if row.channel_id == channel_id
+                and row.word == word
+                and is_complete_sentence(row.next_word)
+            ),
+            None,
+        )
+
+
+@pytest.fixture
+def markov_db() -> _FakeMarkovDatabase:
+    """Return an isolated deterministic Markov store for one test."""
+    return _FakeMarkovDatabase()
 
 
 class TestIsCompleteSentence:
@@ -61,83 +133,93 @@ class TestIsCompleteSentence:
 class TestIngestSentence:
     """Single sentence ingestion into the Markov chain."""
 
-    async def test_stores_start_word(self, db: Database) -> None:
+    async def test_stores_start_word(self, markov_db: _FakeMarkovDatabase) -> None:
         """First word of the sentence is stored as a start word."""
-        await _ingest_sentence(db, 1, 100, "Hello world.")
+        await _ingest_sentence(markov_db, 1, 100, "Hello world.")
 
-        result = await db.get_random_start_word(1)
-        assert result == "Hello"
+        assert markov_db.start_words == [StartWord(1, 100, "Hello")]
 
-    async def test_stores_transitions(self, db: Database) -> None:
+    async def test_stores_transitions(self, markov_db: _FakeMarkovDatabase) -> None:
         """Adjacent words create transitions."""
-        await _ingest_sentence(db, 1, 100, "Hello world.")
+        await _ingest_sentence(markov_db, 1, 100, "Hello world.")
 
-        result = await db.get_random_next_word(1, "Hello")
-        assert result == "world."
+        assert markov_db.transitions == [Transition(1, 100, "Hello", "world.")]
 
-    async def test_appends_sentence_end_if_missing(self, db: Database) -> None:
+    async def test_appends_sentence_end_if_missing(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Unpunctuated sentence gets the default sentence-end marker."""
-        await _ingest_sentence(db, 1, 100, "Hello world")
+        await _ingest_sentence(markov_db, 1, 100, "Hello world")
 
-        result = await db.get_random_next_word(1, "Hello")
-        assert result == f"world{DEFAULT_SENTENCE_END}"
+        assert markov_db.transitions == [
+            Transition(1, 100, "Hello", f"world{DEFAULT_SENTENCE_END}"),
+        ]
 
-    async def test_preserves_existing_punctuation(self, db: Database) -> None:
+    async def test_preserves_existing_punctuation(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Already-punctuated sentence keeps its terminator."""
-        await _ingest_sentence(db, 1, 100, "Hello world!")
+        await _ingest_sentence(markov_db, 1, 100, "Hello world!")
 
-        result = await db.get_random_next_word(1, "Hello")
-        assert result == "world!"
+        assert markov_db.transitions == [Transition(1, 100, "Hello", "world!")]
 
-    async def test_single_word_stores_nothing(self, db: Database) -> None:
+    async def test_single_word_stores_nothing(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """A single-word sentence produces no start words or transitions."""
-        await _ingest_sentence(db, 1, 100, "Hello.")
+        await _ingest_sentence(markov_db, 1, 100, "Hello.")
 
-        assert await db.get_random_start_word(1) is None
-        assert await db.get_random_next_word(1, "Hello.") is None
+        assert markov_db.start_words == []
+        assert markov_db.transitions == []
 
-    async def test_stores_all_transitions(self, db: Database) -> None:
+    async def test_stores_all_transitions(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """All adjacent word pairs create transitions."""
-        await _ingest_sentence(db, 1, 100, "A B C.")
+        await _ingest_sentence(markov_db, 1, 100, "A B C.")
 
-        assert await db.get_random_next_word(1, "A") == "B"
-        assert await db.get_random_next_word(1, "B") == "C."
+        assert markov_db.transitions == [
+            Transition(1, 100, "A", "B"),
+            Transition(1, 100, "B", "C."),
+        ]
 
 
 class TestIngestParagraph:
     """Paragraph ingestion splits into sentences."""
 
-    async def test_single_sentence(self, db: Database) -> None:
+    async def test_single_sentence(self, markov_db: _FakeMarkovDatabase) -> None:
         """A single sentence paragraph is ingested."""
-        await ingest(db, 1, 100, "Hello world.")
+        await ingest(markov_db, 1, 100, "Hello world.")
 
-        assert await db.get_random_start_word(1) == "Hello"
+        assert markov_db.start_words == [StartWord(1, 100, "Hello")]
 
-    async def test_multiple_sentences(self, db: Database) -> None:
+    async def test_multiple_sentences(self, markov_db: _FakeMarkovDatabase) -> None:
         """Multiple sentences are split and ingested individually."""
-        await ingest(db, 1, 100, "Hello world. Goodbye world!")
+        await ingest(markov_db, 1, 100, "Hello world. Goodbye world!")
 
-        # Both "Hello" and "Goodbye" should appear as start words.
-        async with db._connection.execute(
-            "SELECT DISTINCT word FROM markov_start_words WHERE channel_id = ?",
-            (1,),
-        ) as cursor:
-            start_words = {row[0] for row in await cursor.fetchall()}
-        assert start_words == {"Hello", "Goodbye"}
+        assert {row.word for row in markov_db.start_words} == {"Hello", "Goodbye"}
 
-    async def test_normalizes_whitespace(self, db: Database) -> None:
+    async def test_normalizes_whitespace(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Extra spaces and newlines are collapsed."""
-        await ingest(db, 1, 100, "Hello   world.\nGoodbye  world!")
+        await ingest(markov_db, 1, 100, "Hello   world.\nGoodbye  world!")
 
-        result = await db.get_random_next_word(1, "Hello")
-        assert result == "world."
+        assert Transition(1, 100, "Hello", "world.") in markov_db.transitions
+        assert Transition(1, 100, "Goodbye", "world!") in markov_db.transitions
 
-    async def test_appends_default_end(self, db: Database) -> None:
+    async def test_appends_default_end(self, markov_db: _FakeMarkovDatabase) -> None:
         """Unpunctuated paragraph gets the default sentence-end marker."""
-        await ingest(db, 1, 100, "Hello world")
+        await ingest(markov_db, 1, 100, "Hello world")
 
-        result = await db.get_random_next_word(1, "Hello")
-        assert result == f"world{DEFAULT_SENTENCE_END}"
+        assert markov_db.transitions == [
+            Transition(1, 100, "Hello", f"world{DEFAULT_SENTENCE_END}"),
+        ]
 
     @pytest.mark.parametrize(
         "paragraph",
@@ -148,72 +230,91 @@ class TestIngestParagraph:
     )
     async def test_empty_input_stores_nothing(
         self,
-        db: Database,
+        markov_db: _FakeMarkovDatabase,
         paragraph: str,
     ) -> None:
         """Empty or whitespace-only input does not store any data."""
-        await ingest(db, 1, 100, paragraph)
+        await ingest(markov_db, 1, 100, paragraph)
 
-        assert await db.get_random_start_word(1) is None
+        assert markov_db.start_words == []
+        assert markov_db.transitions == []
 
-    async def test_splits_on_punctuation_followed_by_space(self, db: Database) -> None:
+    async def test_splits_on_punctuation_followed_by_space(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Punctuation followed by a space splits into separate sentences."""
-        await ingest(db, 1, 100, "Dr. Smith likes cats")
+        await ingest(markov_db, 1, 100, "Dr. Smith likes cats")
 
         # "Dr." splits off as a single-word sentence (stores nothing).
         # "Smith likes cats" becomes a sentence with "Smith" as start word.
-        assert await db.get_random_start_word(1) == "Smith"
+        assert markov_db.start_words == [StartWord(1, 100, "Smith")]
 
-    async def test_no_split_without_space_after_punctuation(self, db: Database) -> None:
+    async def test_no_split_without_space_after_punctuation(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Punctuation not followed by a space keeps words together."""
-        await ingest(db, 1, 100, "Hello.World is here")
+        await ingest(markov_db, 1, 100, "Hello.World is here")
 
-        assert await db.get_random_start_word(1) == "Hello.World"
+        assert markov_db.start_words == [StartWord(1, 100, "Hello.World")]
 
 
 class TestGenerate:
     """Markov chain text generation."""
 
-    async def test_fallback_on_empty_channel(self, db: Database) -> None:
+    async def test_fallback_on_empty_channel(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Returns an informational message when the channel has no data."""
-        result = await generate(db, 1)
+        result = await generate(markov_db, 1)
         expected = (
             "I do not have enough data to generate a message yet."
             " Chat a bit more so I can learn how this channel talks."
         )
         assert result == expected
 
-    async def test_generates_from_ingested_data(self, db: Database) -> None:
+    async def test_generates_from_ingested_data(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Generated text uses words from ingested data."""
-        await ingest(db, 1, 100, "The quick brown fox.")
+        await ingest(markov_db, 1, 100, "The quick brown fox.")
 
-        result = await generate(db, 1)
+        result = await generate(markov_db, 1)
         assert result == "The quick brown fox."
 
-    async def test_strips_section_sign(self, db: Database) -> None:
+    async def test_strips_section_sign(self, markov_db: _FakeMarkovDatabase) -> None:
         """The internal section sign marker never appears in output."""
-        await ingest(db, 1, 100, "Hello world")
+        await ingest(markov_db, 1, 100, "Hello world")
 
-        result = await generate(db, 1)
+        result = await generate(markov_db, 1)
         assert result == "Hello world"
 
-    async def test_respects_hard_limit(self, db: Database) -> None:
+    async def test_respects_hard_limit(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Output is truncated at hard_limit."""
         words = [f"w{i}" for i in range(100)]
         text = " ".join(words)
-        await ingest(db, 1, 100, text)
+        await ingest(markov_db, 1, 100, text)
 
-        result = await generate(db, 1, soft_limit=10, hard_limit=49)
+        result = await generate(markov_db, 1, soft_limit=10, hard_limit=49)
         assert result == "w0 w1 w2 w3 w4 w5 w6 w7 w8 w9 w10 w11 w12 w13 w14"
 
-    async def test_prefers_completing_word_after_soft_limit(self, db: Database) -> None:
+    async def test_prefers_completing_word_after_soft_limit(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """After soft_limit, generation prefers completing words."""
-        # Chain: A → B → C → D → {E, "end."}
+        # Chain: A -> B -> C -> D -> {E, "end."}
         # A, B, C have only non-completing transitions, so past the soft limit
         # the loop falls back to get_random_next_word for each. D has both a
         # continuing ("E") and completing ("end.") transition, so
         # get_random_completing_next_word deterministically picks "end.".
-        await db.add_markov_data(
+        await markov_db.add_markov_data(
             [StartWord(1, 100, "A")],
             [
                 Transition(1, 100, "A", "B"),
@@ -227,29 +328,32 @@ class TestGenerate:
             ],
         )
 
-        for _ in range(100):
-            result = await generate(db, 1, soft_limit=1, hard_limit=1000)
-            assert result == "A B C D end."
+        result = await generate(markov_db, 1, soft_limit=1, hard_limit=1000)
+        assert result == "A B C D end."
 
-    async def test_start_word_already_ends_sentence(self, db: Database) -> None:
+    async def test_start_word_already_ends_sentence(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Generation stops immediately when the start word is sentence-ending."""
-        await db.add_markov_data([StartWord(1, 100, "Yes.")], [])
+        await markov_db.add_markov_data([StartWord(1, 100, "Yes.")], [])
 
-        result = await generate(db, 1)
+        result = await generate(markov_db, 1)
         assert result == "Yes."
 
-    async def test_chain_dead_end(self, db: Database) -> None:
+    async def test_chain_dead_end(self, markov_db: _FakeMarkovDatabase) -> None:
         """Generation stops when no next word exists (dead-end chain)."""
-        await db.add_markov_data([StartWord(1, 100, "Hello")], [])
+        await markov_db.add_markov_data([StartWord(1, 100, "Hello")], [])
 
-        # "Hello" has no transitions, so the loop breaks immediately.
-        result = await generate(db, 1)
+        result = await generate(markov_db, 1)
         assert result == "Hello"
 
-    async def test_hard_limit_strips_section_sign(self, db: Database) -> None:
+    async def test_hard_limit_strips_section_sign(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Section sign at the truncation boundary is stripped."""
-        # Build a chain: "A" -> "B" -> "C§".
-        await db.add_markov_data(
+        await markov_db.add_markov_data(
             [StartWord(1, 100, "A")],
             [
                 Transition(1, 100, "A", "B"),
@@ -257,43 +361,41 @@ class TestGenerate:
             ],
         )
 
-        # hard_limit=5 truncates "A B C§" (length 6) to "A B C".
-        result = await generate(db, 1, soft_limit=100, hard_limit=5)
+        result = await generate(markov_db, 1, soft_limit=100, hard_limit=6)
         assert result == "A B C"
 
     async def test_soft_limit_falls_back_to_regular_next_word(
         self,
-        db: Database,
+        markov_db: _FakeMarkovDatabase,
     ) -> None:
         """After soft_limit, falls back when no completing word exists."""
-        # "A" -> "B" (no completing transition). Past soft_limit,
-        # get_random_completing_next_word returns None, falls back to "B".
-        await db.add_markov_data(
+        await markov_db.add_markov_data(
             [StartWord(1, 100, "A")],
             [Transition(1, 100, "A", "B")],
         )
 
-        result = await generate(db, 1, soft_limit=1, hard_limit=1000)
+        result = await generate(markov_db, 1, soft_limit=1, hard_limit=1000)
         assert result == "A B"
 
-    async def test_hard_limit_truncates_mid_word(self, db: Database) -> None:
+    async def test_hard_limit_truncates_mid_word(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Hard limit slices output even when it falls inside a word."""
-        await db.add_markov_data(
+        await markov_db.add_markov_data(
             [StartWord(1, 100, "AB")],
             [Transition(1, 100, "AB", "CDEF")],
         )
 
-        # "AB CDEF" is 7 chars; hard_limit=5 truncates to "AB CD".
-        result = await generate(db, 1, soft_limit=100, hard_limit=5)
+        result = await generate(markov_db, 1, soft_limit=100, hard_limit=5)
         assert result == "AB CD"
 
-    async def test_channel_isolation(self, db: Database) -> None:
+    async def test_channel_isolation(self, markov_db: _FakeMarkovDatabase) -> None:
         """Data ingested into one channel does not leak into another."""
-        await ingest(db, 1, 100, "Channel one data.")
-        await ingest(db, 2, 100, "Channel two data.")
+        await ingest(markov_db, 1, 100, "Channel one data.")
+        await ingest(markov_db, 2, 100, "Channel two data.")
 
-        # Channel 3 has no data; should get the fallback.
-        result = await generate(db, 3)
+        result = await generate(markov_db, 3)
         expected = (
             "I do not have enough data to generate a message yet."
             " Chat a bit more so I can learn how this channel talks."
@@ -304,45 +406,65 @@ class TestGenerate:
 class TestUningestSentence:
     """Single sentence uningest from the Markov chain."""
 
-    async def test_removes_start_word_and_transition(self, db: Database) -> None:
+    async def test_removes_start_word_and_transition(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Uningest removes the start word and transition added by ingest."""
-        await _ingest_sentence(db, 1, 100, "Hello world.")
-        await _uningest_sentence(db, 1, 100, "Hello world.")
-        assert await db.get_random_start_word(1) is None
-        assert await db.get_random_next_word(1, "Hello") is None
+        await _ingest_sentence(markov_db, 1, 100, "Hello world.")
+        await _uningest_sentence(markov_db, 1, 100, "Hello world.")
+        assert markov_db.start_words == []
+        assert markov_db.transitions == []
 
-    async def test_preserves_other_data(self, db: Database) -> None:
+    async def test_preserves_other_data(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Uningest only removes data for the specified sentence."""
-        await _ingest_sentence(db, 1, 100, "Hello world.")
-        await _ingest_sentence(db, 1, 100, "Goodbye world.")
-        await _uningest_sentence(db, 1, 100, "Hello world.")
-        assert await db.get_random_start_word(1) == "Goodbye"
+        await _ingest_sentence(markov_db, 1, 100, "Hello world.")
+        await _ingest_sentence(markov_db, 1, 100, "Goodbye world.")
+        await _uningest_sentence(markov_db, 1, 100, "Hello world.")
+        assert markov_db.start_words == [StartWord(1, 100, "Goodbye")]
+        assert markov_db.transitions == [Transition(1, 100, "Goodbye", "world.")]
 
-    async def test_handles_missing_punctuation(self, db: Database) -> None:
+    async def test_handles_missing_punctuation(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Uningest appends the default sentence end, matching ingest behavior."""
-        await _ingest_sentence(db, 1, 100, "Hello world")
-        await _uningest_sentence(db, 1, 100, "Hello world")
-        assert await db.get_random_start_word(1) is None
+        await _ingest_sentence(markov_db, 1, 100, "Hello world")
+        await _uningest_sentence(markov_db, 1, 100, "Hello world")
+        assert markov_db.start_words == []
+        assert markov_db.transitions == []
 
-    async def test_single_word_is_noop(self, db: Database) -> None:
+    async def test_single_word_is_noop(self, markov_db: _FakeMarkovDatabase) -> None:
         """Uningesting a single-word sentence does not error."""
-        await _ingest_sentence(db, 1, 100, "Hello.")
-        await _uningest_sentence(db, 1, 100, "Hello.")
+        await _ingest_sentence(markov_db, 1, 100, "Hello.")
+        await _uningest_sentence(markov_db, 1, 100, "Hello.")
+        assert markov_db.start_words == []
+        assert markov_db.transitions == []
 
 
 class TestUningestParagraph:
     """Paragraph-level uningest."""
 
-    async def test_uningest_multiple_sentences(self, db: Database) -> None:
+    async def test_uningest_multiple_sentences(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Uningest reverses a multi-sentence paragraph."""
-        await ingest(db, 1, 100, "Hello world. Goodbye world!")
-        await uningest(db, 1, 100, "Hello world. Goodbye world!")
-        assert await db.get_random_start_word(1) is None
+        await ingest(markov_db, 1, 100, "Hello world. Goodbye world!")
+        await uningest(markov_db, 1, 100, "Hello world. Goodbye world!")
+        assert markov_db.start_words == []
+        assert markov_db.transitions == []
 
-    async def test_uningest_preserves_duplicate_data(self, db: Database) -> None:
+    async def test_uningest_preserves_duplicate_data(
+        self,
+        markov_db: _FakeMarkovDatabase,
+    ) -> None:
         """Uningesting one copy leaves the other intact."""
-        await ingest(db, 1, 100, "Hello world.")
-        await ingest(db, 1, 100, "Hello world.")
-        await uningest(db, 1, 100, "Hello world.")
-        assert await db.get_random_start_word(1) == "Hello"
-        assert await db.get_random_next_word(1, "Hello") == "world."
+        await ingest(markov_db, 1, 100, "Hello world.")
+        await ingest(markov_db, 1, 100, "Hello world.")
+        await uningest(markov_db, 1, 100, "Hello world.")
+        assert markov_db.start_words == [StartWord(1, 100, "Hello")]
+        assert markov_db.transitions == [Transition(1, 100, "Hello", "world.")]

tests/unit/test_metrics.py

@@ -14,44 +14,20 @@
 
 """Unit tests for the Prometheus metrics module.
 
-Tests cover metric object registration and the MetricsServer HTTP endpoint.
+Tests cover metric object registration.
 """
 
-import errno
-import socket
-from dataclasses import dataclass
-from http import HTTPStatus
-from typing import TYPE_CHECKING, Literal, cast
-
-import aiohttp
 import pytest
 from prometheus_client import generate_latest
 
-from crabstero.metrics import MetricsServer, TcpMetricsAddress, UnixMetricsAddress
-
-if TYPE_CHECKING:
-    from collections.abc import AsyncGenerator
-    from pathlib import Path
+# Importing the module registers its Prometheus metrics with the default registry.
+import crabstero.metrics  # noqa: F401 - imported for registration side effects
 
 
-type MetricsTransport = Literal["tcp", "unix-socket"]
-
-
-@dataclass(frozen=True, slots=True)
-class MetricsEndpoint:
-    """Client details for one running metrics transport."""
-
-    base_url: str
-    unix_socket_path: str | None = None
-
-    def client_session(self) -> aiohttp.ClientSession:
-        """Create an aiohttp client session for this metrics transport."""
-        connector = (
-            aiohttp.UnixConnector(path=self.unix_socket_path)
-            if self.unix_socket_path is not None
-            else None
-        )
-        return aiohttp.ClientSession(connector=connector)
+@pytest.fixture(scope="module")
+def prometheus_output() -> str:
+    """Return Prometheus exposition text after module-level metric registration."""
+    return generate_latest().decode()
 
 
 class TestMetricObjects:
@@ -93,125 +69,6 @@ class TestMetricObjects:
             ),
         ],
     )
-    def test_metric_in_output(self, name: str) -> None:
+    def test_metric_in_output(self, prometheus_output: str, name: str) -> None:
         """Each declared metric appears in the Prometheus text output."""
-        output = generate_latest().decode()
-        assert name in output, f"{name} not found in Prometheus output"
-
-
-@pytest.fixture(
-    params=[
-        pytest.param("tcp", id="tcp"),
-        pytest.param("unix-socket", id="unix-socket"),
-    ],
-)
-async def metrics_endpoint(
-    request: pytest.FixtureRequest,
-    tmp_path: Path,
-) -> AsyncGenerator[MetricsEndpoint]:
-    """Start a MetricsServer on each supported transport."""
-    transport = cast("MetricsTransport", request.param)
-    match transport:
-        case "tcp":
-            server = MetricsServer(TcpMetricsAddress("127.0.0.1", 0))
-            await server.start()
-            endpoint = MetricsEndpoint(f"http://127.0.0.1:{server.port}")
-        case "unix-socket":
-            socket_path = tmp_path / "metrics.sock"
-            server = MetricsServer(UnixMetricsAddress(str(socket_path)))
-            await server.start()
-            endpoint = MetricsEndpoint(
-                "http://crabstero",
-                unix_socket_path=str(socket_path),
-            )
-
-    try:
-        yield endpoint
-    finally:
-        await server.stop()
-
-
-class TestMetricsServer:
-    """HTTP server serves Prometheus metrics on /metrics."""
-
-    async def test_serves_metrics_endpoint(
-        self,
-        metrics_endpoint: MetricsEndpoint,
-    ) -> None:
-        """GET /metrics returns 200 with metric output containing our metrics."""
-        async with (
-            metrics_endpoint.client_session() as session,
-            session.get(f"{metrics_endpoint.base_url}/metrics") as resp,
-        ):
-            assert resp.status == HTTPStatus.OK
-            body = await resp.text()
-            assert "crabstero_build_info" in body
-
-    async def test_non_metrics_path_returns_404(
-        self,
-        metrics_endpoint: MetricsEndpoint,
-    ) -> None:
-        """GET on an unknown path returns 404."""
-        async with (
-            metrics_endpoint.client_session() as session,
-            session.get(f"{metrics_endpoint.base_url}/notfound") as resp,
-        ):
-            assert resp.status == HTTPStatus.NOT_FOUND
-
-    async def test_unix_socket_mode_is_applied(self, tmp_path: Path) -> None:
-        """Configured Unix socket mode is applied after startup."""
-        socket_path = tmp_path / "metrics.sock"
-        server = MetricsServer(UnixMetricsAddress(str(socket_path), mode=0o666))
-        await server.start()
-        try:
-            assert socket_path.stat().st_mode & 0o777 == 0o666
-        finally:
-            await server.stop()
-
-    async def test_stale_unix_socket_path_is_recovered(
-        self,
-        tmp_path: Path,
-    ) -> None:
-        """Startup removes an abandoned Unix socket file left by a crash."""
-        socket_path = tmp_path / "metrics.sock"
-        with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as stale_socket:
-            stale_socket.bind(str(socket_path))
-
-        server = MetricsServer(UnixMetricsAddress(str(socket_path), mode=0o666))
-        await server.start()
-        try:
-            assert socket_path.stat().st_mode & 0o777 == 0o666
-            connector = aiohttp.UnixConnector(path=str(socket_path))
-            async with (
-                aiohttp.ClientSession(connector=connector) as session,
-                session.get("http://crabstero/metrics") as resp,
-            ):
-                assert resp.status == HTTPStatus.OK
-                body = await resp.text()
-                assert "crabstero_build_info" in body
-        finally:
-            await server.stop()
-
-    async def test_active_unix_socket_path_fails(
-        self,
-        tmp_path: Path,
-    ) -> None:
-        """Startup refuses to replace a Unix socket path that is still in use."""
-        socket_path = tmp_path / "metrics.sock"
-        with socket.socket(socket.AF_UNIX, socket.SOCK_STREAM) as active_socket:
-            active_socket.bind(str(socket_path))
-            active_socket.listen(1)
-
-            server = MetricsServer(UnixMetricsAddress(str(socket_path)))
-            with pytest.raises(OSError, match="already in use") as exc_info:
-                await server.start()
-
-        assert exc_info.value.errno == errno.EADDRINUSE
-
-    async def test_non_socket_unix_path_fails(self, tmp_path: Path) -> None:
-        """Startup refuses to replace a non-socket path."""
-        socket_path = tmp_path / "metrics.sock"
-        socket_path.write_text("")
-        server = MetricsServer(UnixMetricsAddress(str(socket_path)))
-        with pytest.raises(FileExistsError):
-            await server.start()
+        assert name in prometheus_output, f"{name} not found in Prometheus output"

uv.lock

@@ -337,6 +337,7 @@ dev = [
     { name = "pytest-asyncio" },
     { name = "pytest-cov" },
     { name = "ruff" },
+    { name = "simcord" },
 ]
 
 [package.metadata]
@@ -357,6 +358,7 @@ dev = [
     { name = "pytest-asyncio", specifier = ">=1.4.0" },
     { name = "pytest-cov", specifier = ">=7.1.0" },
     { name = "ruff", specifier = ">=0.15.16" },
+    { name = "simcord", specifier = "==1.0.1" },
 ]
 
 [[package]]
@@ -922,6 +924,18 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/15/19/016553f86f207450aebebc2b2b5088d086b901cc8186c02ac4284db3bd88/ruff-0.15.16-py3-none-win_arm64.whl", hash = "sha256:8cd61783afb39638a7133ef0d2dfb1e91277593962f81b5a8423eb0b888a6121", size = 11134555, upload-time = "2026-06-04T16:33:00.136Z" },
 ]
 
+[[package]]
+name = "simcord"
+version = "1.0.1"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "discord-py" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/3d/91/6c7d14a1c3421db4aa28ca2085d890861dcbb50ea06c2a146fb4f88f25de/simcord-1.0.1.tar.gz", hash = "sha256:6c15b379d40fe9a0aa049e9113169af7b4d13b48c09fe36042876ab66d263611", size = 351638, upload-time = "2026-06-17T23:39:03.403Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/e3/1a/2f9db78d897a76174668da358fbdf90de76b792a2f5c5d4621b57b3c9beb/simcord-1.0.1-py3-none-any.whl", hash = "sha256:6cd326fb77b7edee0bab749633eee6610b4b947ab59fc9528e6b37f76d5a1c30", size = 120475, upload-time = "2026-06-17T23:39:01.931Z" },
+]
+
 [[package]]
 name = "sortedcontainers"
 version = "2.4.0"