Websocket testing on ASGI app results in "The future belongs to a different loop" error

[roysagi]

I am currently working on an app based on fastapi. Up until now the app only supported HTTP calls and I am now trying to add a websocket call which is based on a different HTTP call, both calls use the same dependencies.

The HTTP call works fine in testing but for some reason the websocket call is constantly getting this error in unit tests:

 httpx_ws._api.WebSocketDisconnect: (<CloseReason.INTERNAL_ERROR: 1011>, 'The future belongs to a different loop than the one specified as the loop argument')

I am guessing the test client is using a different loop than the app which results in this error for some reason (?)
Any way I can set the loop used by the test client? or any other means to fix this issue?

here is my test code:

async def test_websocket(
     test_api_user_token, app
):
    async with AsyncClient(
        app=app,
        transport=ASGIWebSocketTransport(app, raise_app_exceptions=False),
        base_url="https://testserver",
    ) as client:
        client.headers = {"Authorization": f"Bearer {test_api_user_token}"}

        async with aconnect_ws(f"ws://testserver/ws", client) as websocket:
            await asyncio.sleep(3)

Any help here would be appreciated.

[frankie567]

Two things to check:

1. Don't set the app argument on AsyncClient, only transport argument is necessary
2. I suppose you use pytest-asyncio to run async tests. Make sure you define the event_loop fixture as described here: https://pytest-asyncio.readthedocs.io/en/latest/reference/fixtures.html#fixtures