async def mock_run_sync_activity_no_heartbeat(*args, **kwargs):
                """Simulate an activity that stops heartbeating (worker dies)."""
                # Don't send any heartbeats - simulate dead worker
                await asyncio.sleep(300)  # Sleep longer than heartbeat timeout
Simulate an activity that stops heartbeating (worker dies).
backend/tests/integration/temporal/test_workflow_cancellation.py