Backend test hardening + quality enforcement (#872)

- Reworked many tests
- Enforcing lint + type checking for test suite
- Fixed various issues surfaced by the new tests
- CI tweaks

tests/irc/test_source.py

@@ -1,3 +1,7 @@
+from types import SimpleNamespace
+
+from shelfmark.metadata_providers import BookMetadata
+from shelfmark.release_sources import Release
 from shelfmark.release_sources.irc.parser import SearchResult
 from shelfmark.release_sources.irc.source import IRCReleaseSource
 
@@ -29,3 +33,107 @@ def test_convert_to_releases_marks_audiobook_results_and_sorts_audio_before_arch
 
     assert [release.format for release in releases] == ["m4b", "zip"]
     assert all(release.content_type == "audiobook" for release in releases)
+
+
+def test_search_uses_cached_results_without_opening_a_connection(monkeypatch):
+    import shelfmark.release_sources.irc.source as irc_source
+
+    source = IRCReleaseSource()
+    cached_release = Release(
+        source="irc",
+        source_id="cached-line",
+        title="Cached Result",
+    )
+
+    monkeypatch.setattr(source, "is_available", lambda: True)
+    monkeypatch.setattr(
+        "shelfmark.release_sources.irc.cache.get_cached_results",
+        lambda provider, provider_id, *, content_type: {
+            "releases": [cached_release],
+            "online_servers": ["AudioBot"],
+        },
+    )
+    monkeypatch.setattr(
+        "shelfmark.release_sources.irc.connection_manager.connection_manager.get_connection",
+        lambda **_kwargs: (_ for _ in ()).throw(
+            AssertionError("cache hit should skip IRC connection")
+        ),
+    )
+    monkeypatch.setattr(irc_source, "_emit_status", lambda *_args, **_kwargs: None)
+
+    book = BookMetadata(provider="hardcover", provider_id="123", title="Cached Book")
+    plan = SimpleNamespace(primary_query="Cached Book")
+
+    releases = source.search(book, plan)
+
+    assert releases == [cached_release]
+    assert source._online_servers == {"AudioBot"}
+
+
+def test_search_no_dcc_offer_releases_connection_and_caches_empty_result(monkeypatch):
+    import shelfmark.release_sources.irc.source as irc_source
+
+    source = IRCReleaseSource()
+    cache_calls: list[dict[str, object]] = []
+    released_clients: list[object] = []
+
+    class FakeClient:
+        online_servers = {"AudioBot"}
+
+        def send_message(self, channel: str, message: str) -> None:
+            self.channel = channel
+            self.message = message
+
+        def wait_for_dcc(self, *, timeout: float, result_type: bool) -> None:
+            return None
+
+    client = FakeClient()
+
+    monkeypatch.setattr(source, "is_available", lambda: True)
+    monkeypatch.setattr(irc_source, "_enforce_rate_limit", lambda: None)
+    monkeypatch.setattr(irc_source, "_emit_status", lambda *_args, **_kwargs: None)
+    monkeypatch.setattr(
+        "shelfmark.release_sources.irc.cache.get_cached_results",
+        lambda provider, provider_id, *, content_type: None,
+    )
+    monkeypatch.setattr(
+        "shelfmark.release_sources.irc.cache.cache_results",
+        lambda provider, provider_id, title, releases, *, content_type, online_servers: (
+            cache_calls.append(
+                {
+                    "provider": provider,
+                    "provider_id": provider_id,
+                    "title": title,
+                    "releases": releases,
+                    "content_type": content_type,
+                    "online_servers": online_servers,
+                }
+            )
+        ),
+    )
+    monkeypatch.setattr(
+        "shelfmark.release_sources.irc.connection_manager.connection_manager.get_connection",
+        lambda **_kwargs: client,
+    )
+    monkeypatch.setattr(
+        "shelfmark.release_sources.irc.connection_manager.connection_manager.release_connection",
+        lambda released_client: released_clients.append(released_client),
+    )
+
+    book = BookMetadata(provider="hardcover", provider_id="abc", title="Missing Result")
+    plan = SimpleNamespace(primary_query="Missing Result")
+
+    releases = source.search(book, plan, content_type="audiobook")
+
+    assert releases == []
+    assert released_clients == [client]
+    assert cache_calls == [
+        {
+            "provider": "hardcover",
+            "provider_id": "abc",
+            "title": "Missing Result",
+            "releases": [],
+            "content_type": "audiobook",
+            "online_servers": ["AudioBot"],
+        }
+    ]