RuntimeError: There is no current event loop in thread 'MainThread'.

[qci-amos]

My previously passing test is now failing with pytest-asyncio==0.22. I get the error:

self = <Coroutine test_my_test[0]>

    def runtest(self) -> None:
        if self.get_closest_marker("asyncio"):
            self.obj = wrap_in_sync(
                # https://github.com/pytest-dev/pytest-asyncio/issues/596
                self.obj,  # type: ignore[has-type]
            )
>       super().runtest()

../../../miniconda3/envs/py311/lib/python3.11/site-packages/pytest_asyncio/plugin.py:426:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
../../../miniconda3/envs/py311/lib/python3.11/site-packages/pytest_asyncio/plugin.py:804: in inner
    _loop = asyncio.get_event_loop()
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
self = <asyncio.unix_events._UnixDefaultEventLoopPolicy object at 0x7f5a92b814d0>

    def get_event_loop(self):
        """Get the event loop for the current context.

        Returns an instance of EventLoop or raises an exception.
        """
        if (self._local._loop is None and
                not self._local._set_called and
                threading.current_thread() is threading.main_thread()):
            self.set_event_loop(self.new_event_loop())

        if self._local._loop is None:
>           raise RuntimeError('There is no current event loop in thread %r.'
                               % threading.current_thread().name)
E           RuntimeError: There is no current event loop in thread 'MainThread'.

../../../miniconda3/envs/py311/lib/python3.11/asyncio/events.py:677: RuntimeError

I assume it's a coincidence, but just yesterday I switched from

pytestmark = pytest.mark.asyncio

to:

[tool.pytest.ini_options]
asyncio_mode = "auto"

[2e0byo]

Do you have a custom event loop fixture? I had (apparently) random failures of this kind in our test suite with this upgrade, only where a custom fixture was being used. I didn't investigate further. (We have always used asyncio_mode = "auto" btw)

[Pliner]

We have the same issue as @qci-amos reported (out setup.cfg contains [tool.pytest.ini_options] asyncio_mode = "auto").

[seifertm]

@qci-amos Can you provide the sources of test_my_test?

If you provide a short code example the reproduces the error, I'm happy to look into it.

As a temporary workaround, you can pin your version of pytest-asyncio to pytest-asyncio!=0.22.0

[lindycoder]

Thank you for fixing by removing 0.22.0.

I would like to share something regarding this warning:

PytestDeprecationWarning: xxxxxxxx is asynchronous and explicitly requests the "event_loop" fixture. Asynchronous fixtures and test functions should use "asyncio.get_running_loop()" instead.

We have session scoped async fixtures so we have this central fixture

@pytest.fixture(scope="session")
def event_loop() -> Generator[AbstractEventLoop, None, None]:
    """Make the loop session scope to use session async fixtures."""
    policy = asyncio.get_event_loop_policy()
    loop = policy.new_event_loop()
    yield loop
    loop.close()

And every single AsyncGenerator fixtures we have actually require event_loop to make sure the teardown is done before the loop is closed.

Sharing this use-case hoping to help further development.

[2e0byo]

@lindycoder larger scopes are being discussed over here #657

[gabrielmbmb]

Hey guys, just wanted to mention that pytest-asyncio==0.22.0 hasn't been yanked in conda-forge https://anaconda.org/conda-forge/pytest-asyncio

[seifertm]

@lindycoder Thanks for sharing your use case. These things are highly valuable for the pytest-asyncio devs.

@gabrielmbmb I created an account on anaconda and looked for way to claim or flag the package, but didn't find any. Do you have any information what the procedure is for yanking packages on conda-forge? It seems there is none.

[seifertm]

@gabrielmbmb I filed a PR to mark pytest-asyncio v0.22.0 as broken on conda-forge:
conda-forge/admin-requests#857

[gabrielmbmb]

Thanks @seifertm!

[qci-amos]

Unfortunately, I've already forgotten exactly which test this was! However, since this test used a @pytest.fixture(scope="session"), it seems almost certain now that this issue is effectively a duplicate of #657

[seifertm]

Since this seems to be related to session-scoped loops in v0.22.0, I'll close the issue as a duplicate as you suggested.

If you're interested to test out the upcoming release, pytest-asyncio v0.23.0a0 is available on PyPI and adds an optional scope keyword argument to the asyncio mark to control the scope used for each test. I'd appreciate your feedback on the pre-release version.