feat: manual match pin/unpin endpoints

backend/tests/conftest.py

@@ -155,6 +155,19 @@ def db(_engine):
         connection.close()
 
 
+@pytest.fixture()
+def db_session():
+    """Plain SessionLocal for tests that need to seed data outside the
+    transactional ``db`` fixture (e.g. setting up rows the API will read)."""
+    from app.database import SessionLocal
+
+    s = SessionLocal()
+    try:
+        yield s
+    finally:
+        s.close()
+
+
 @pytest.fixture()
 def client(db):
     """TestClient with get_db overridden to yield the test session."""