RuntimeError: Task attached to a different loop

Root cause

Background task and asyncio.Queue for FastAPI webhook worker were initialized during a session-scoped app/client fixture before pytest-asyncio reset the event loop for the test function. The request handler then awaited queue.put() from a different loop than the one that owns the worker queue/future.

Minimal fix

Make the async app/client fixture function-scoped, create the FastAPI app and webhook worker inside the active pytest-asyncio event loop, and explicitly await the app lifespan/startup before issuing requests. Avoid constructing asyncio.Queue or create_task at module import or in session-scoped fixtures; shut the worker down in fixture teardown.