diff --git a/features/steps/tdd_langgraph_execute_closed_state_steps.py b/features/steps/tdd_langgraph_execute_closed_state_steps.py
index f4fe2d7ad..ab710b1ac 100644
--- a/features/steps/tdd_langgraph_execute_closed_state_steps.py
+++ b/features/steps/tdd_langgraph_execute_closed_state_steps.py
@@ -56,7 +56,7 @@ def step_assert_runtime_error(context: Context) -> None:
     )
     assert "StateManager is closed" in str(context.execute_error), (
         f'Expected "StateManager is closed" in error message, '
-        f'got: {context.execute_error}'
+        f"got: {context.execute_error}"
     )