fix(tests): add mypy type assertions for nullable returns

- Add assert is not None before accessing Account attributes
- Add type annotation for empty dict in test
- Add type ignore for unreachable fixture cleanup

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: joachimBrindeau

tests/integration/test_db_integration.py

@@ -24,9 +24,9 @@ async def temp_db():
         await init_db(db_path)
         yield db_path
 
-        # Cleanup
+        # Cleanup (runs after test completes)
         if engine_module._engine:
-            await engine_module._engine.dispose()
+            await engine_module._engine.dispose()  # type: ignore[unreachable]
 
 
 @pytest.mark.asyncio
@@ -55,6 +55,7 @@ async def test_full_account_lifecycle(temp_db):
         refresh_token="new_refresh",
         expires_at=datetime.now(UTC) + timedelta(hours=2),
     )
+    assert updated is not None
     assert updated.access_token == "new_access"
 
     # List

tests/unit/db/test_migration.py

@@ -92,6 +92,7 @@ async def test_migrate_skips_existing(setup):
 
     # Verify original data preserved
     account = await repo.get("existing")
+    assert account is not None
     assert account.access_token == "db_access"  # Not overwritten
 
 
@@ -169,7 +170,7 @@ async def test_migrate_empty_accounts(setup):
     tmpdir, db_path, json_path = setup
 
     # Create accounts.json with empty accounts
-    accounts_data = {"accounts": {}}
+    accounts_data: dict[str, dict[str, dict[str, str]]] = {"accounts": {}}
     json_path.write_text(json.dumps(accounts_data))
 
     # Run migration
@@ -227,9 +228,11 @@ async def test_migrate_partial_success(setup):
 
     # Verify both accounts exist with correct data
     existing = await repo.get("existing")
+    assert existing is not None
     assert existing.access_token == "db_access"  # Not overwritten
 
     new = await repo.get("new-account")
+    assert new is not None
     assert new.access_token == "new_access"