diff --git a/backend/src/test/conftest.py b/backend/src/test/conftest.py
index 5f8cd408..fa856fd7 100644
--- a/backend/src/test/conftest.py
+++ b/backend/src/test/conftest.py
@@ -8,6 +8,7 @@ from fastapi.testclient import TestClient
 from sqlmodel import Session, SQLModel, create_engine
 
 from module.api import v1
+from module.database.bangumi import _invalidate_bangumi_cache
 from module.models.config import Config
 from module.models import ResponseModel
 from module.security.api import get_current_user
@@ -18,6 +19,19 @@ from module.security.api import get_current_user
 # ---------------------------------------------------------------------------
 
 
+@pytest.fixture(autouse=True)
+def _clear_bangumi_cache():
+    """Invalidate the module-level bangumi cache before each test.
+
+    The BangumiDatabase.search_all() uses a module-level TTL cache that
+    persists across tests using different in-memory databases, causing
+    stale results.
+    """
+    _invalidate_bangumi_cache()
+    yield
+    _invalidate_bangumi_cache()
+
+
 @pytest.fixture
 def db_engine():
     """Create an in-memory SQLite engine for testing."""