def pytest_fixture_setup(fixturedef):  # type: ignore[no-untyped-def]
    """Set up pytest fixture.

    Allow fixtures to be coroutines. Run coroutine fixtures in an event loop.
    """
    func = fixturedef.func

    if isasyncgenfunction(func):
        # async generator fixture
        is_async_gen = True
    elif asyncio.iscoroutinefunction(func):
        # regular async fixture
        is_async_gen = False
    else:
        # not an async fixture, nothing to do
        return

    strip_request = False
    if "request" not in fixturedef.argnames:
        fixturedef.argnames += ("request",)
        strip_request = True

    def wrapper(*args, **kwargs):  # type: ignore[no-untyped-def]
        request = kwargs["request"]
        if strip_request:
            del kwargs["request"]

        # if neither the fixture nor the test use the 'loop' fixture,
        # 'getfixturevalue' will fail because the test is not parameterized
        # (this can be removed someday if 'loop' is no longer parameterized)
        if "loop" not in request.fixturenames:
            raise Exception(
                "Asynchronous fixtures must depend on the 'loop' fixture or "
                "be used in tests depending from it."
            )

        _loop = request.getfixturevalue("loop")

        if is_async_gen:
            # for async generators, we need to advance the generator once,
            # then advance it again in a finalizer
            gen = func(*args, **kwargs)

            def finalizer():  # type: ignore[no-untyped-def]
                try:
                    return _loop.run_until_complete(gen.__anext__())
                except StopAsyncIteration:
                    pass

            request.addfinalizer(finalizer)
            return _loop.run_until_complete(gen.__anext__())
        else:
            return _loop.run_until_complete(func(*args, **kwargs))

    fixturedef.func = wrapper
Set up pytest fixture.

    Allow fixtures to be coroutines. Run coroutine fixtures in an event loop.
    
lib/aiohttp/pytest_plugin.py