refine teardown

backend/tests/test_crud.py

@@ -24,7 +24,6 @@ def engine() -> Generator[Engine, None, None]:
         yield e
     finally:
         SQLModel.metadata.drop_all(e)
-        SQLModel.metadata.clear()
         e.dispose()
 
 

backend/tests/test_db.py

@@ -42,7 +42,6 @@ def database_ctx(db: Database) -> Generator[Database, None, None]:
         yield db
     finally:
         db.dispose()
-        SQLModel.metadata.clear()
 
 
 def test_select_one_executes() -> None:
@@ -77,6 +76,7 @@ def test_sqlite_pragmas_applied() -> None:
 
 def test_rollback_on_exception() -> None:
     db = create_database(None)
+    SQLModel.metadata.clear()
     db.init_db()
     with database_ctx(db):
         # Create table then insert and raise inside the same session to force rollback

backend/tests/test_db_migration.py

@@ -13,6 +13,7 @@ def _base_type_of(compiled: str) -> str:
 
 def test_run_migrations_0_to_1(monkeypatch: pytest.MonkeyPatch) -> None:
     # in-memory engine that preserves the same connection (StaticPool)
+    SQLModel.metadata.clear()
     engine = create_engine(
         "sqlite:///:memory:",
         connect_args={"check_same_thread": False},