documentation on how to force all tests in one session to use the same event loop appears to not force fixtures into the same event loop about pytest-asyncio

[seifertm]

You'd better move to prior version. -> 0.21.1. I also wasted a day, figuring out why contextvar got spawend on another event_loop.

I agree. If pytest-asyncio v0.23 is currently causing issues for you, I suggest to continue using v0.21 until the issues are resolved.

@danking The v0.23 release allows tests to be run in different event loops. There's essentially one loop for each hierarchy level of the test suite (session, package, module, class, function). Unfortunately, pytest-asyncio also assumes that the scope of a fixture is coupled with the scope of the event loop. This means that a session-scoped fixture always runs in the session-scope loop. There's currently no way to have a session-scoped fixture running in the same loop as a function-scoped test. This is the core issue of #706.

@rumbarum I'm sorry that this caused you spending so much time on this issue.

[rumbarum]

@seifertm
I appreciate your works.
And thanks for your words.

[danking]

This is definitely related to #706, #705, and #718, but I think my essential ask here is for documentation on how to ensure a particular test (or scope of tests, or group of tests) uses the same event loop as a particular fixture (or scope of fixtures, or group of fixtures).

The example I gave above may seem contrived, but it's essential to the correct functioning of aiohttp. The aiohttp.ClientSession saves a copy of the event loop at allocation time and assumes the same event loop is in use at HTTP request time.

If I have any non-default scoped fixture that creates a client session (possibly multiple layers down from the object I'm actually allocating), that fixture will yield a (nondeterministically) broken client session.

[rumbarum]

#706 (comment)

You'd better move to prior version. -> 0.21.1.
I also wasted a day, figuring out why contextvar got spawend on another event_loop.