testsuite fails on python-3.9.7 due to new deprecation warnings (worked on 3.9.6)

[trofi]

Describe the bug

After updating to python-3.9.7 from python-3.9.6 aiohttp testsuite started failing as:

    async def sleep(delay, result=None, *, loop=None):
        """Coroutine that completes after a given time (in seconds)."""
        if loop is not None:
>           warnings.warn("The loop argument is deprecated since Python 3.8, "
                          "and scheduled for removal in Python 3.10.",
                          DeprecationWarning, stacklevel=2)
E           DeprecationWarning: The loop argument is deprecated since Python 3.8, and scheduled for removal in Python 3.10.

/nix/store/56c5lnijckyrvczz03sgqs236x693fjf-python3-3.9.7/lib/python3.9/asyncio/tasks.py:639: DeprecationWarning

To Reproduce

Update to python-3.9.7 and run the testsuite.

Expected behavior

The tests should pass.

Logs/tracebacks

Example failure of the first failing test:


_______________________ ERROR at setup of test_get_route _______________________

loop = <_UnixSelectorEventLoop running=False closed=False debug=False>
app = <Application 0x7ffff3ac2670>

    @pytest.fixture
    def test_client(loop, app) -> None:
        async def make_client():
            return _TestClient(_TestServer(app, loop=loop), loop=loop)

        client = loop.run_until_complete(make_client())

>       loop.run_until_complete(client.start_server())

test_test_utils.py:73:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
/nix/store/56c5lnijckyrvczz03sgqs236x693fjf-python3-3.9.7/lib/python3.9/asyncio/base_events.py:642: in run_until_complete
    return future.result()
/nix/store/zrkj2d2mis6vmg360x6zdxl2pmghiili-python3.9-aiohttp-3.7.4.post0/lib/python3.9/site-packages/aiohttp/test_utils.py:268: in start_server
    await self._server.start_server(loop=self._loop)
/nix/store/zrkj2d2mis6vmg360x6zdxl2pmghiili-python3.9-aiohttp-3.7.4.post0/lib/python3.9/site-packages/aiohttp/test_utils.py:113: in start_server
    await site.start()
/nix/store/zrkj2d2mis6vmg360x6zdxl2pmghiili-python3.9-aiohttp-3.7.4.post0/lib/python3.9/site-packages/aiohttp/web_runner.py:230: in start
    self._server = await loop.create_server(
/nix/store/56c5lnijckyrvczz03sgqs236x693fjf-python3-3.9.7/lib/python3.9/asyncio/base_events.py:1518: in create_server
    await tasks.sleep(0, loop=self)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

delay = 0, result = None

    async def sleep(delay, result=None, *, loop=None):
        """Coroutine that completes after a given time (in seconds)."""
        if loop is not None:
>           warnings.warn("The loop argument is deprecated since Python 3.8, "
                          "and scheduled for removal in Python 3.10.",
                          DeprecationWarning, stacklevel=2)
E           DeprecationWarning: The loop argument is deprecated since Python 3.8, and scheduled for removal in Python 3.10.

/nix/store/56c5lnijckyrvczz03sgqs236x693fjf-python3-3.9.7/lib/python3.9/asyncio/tasks.py:639: DeprecationWarning

### Python Version

```console
$ python --version
Python 3.9.7

aiohttp Version

$ python -m pip show aiohttp
WARNING: Package(s) not found: aiohttp

multidict Version

$ python -m pip show multidict
Name: multidict
Version: 5.1.0
Summary: multidict implementation
Home-page: https://github.com/aio-libs/multidict
Author: Andrew Svetlov
Author-email: [email protected]
License: Apache 2
Location: /nix/store/fdvkz2jvqc8ra426yp3m74ynq71g13vz-python3.9-multidict-5.1.0/lib/python3.9/site-packages
Requires:
Required-by: yarl

yarl Version

$ python -m pip show yarl
Name: yarl
Version: 1.6.3
Summary: Yet another URL library
Home-page: https://github.com/aio-libs/yarl/
Author: Andrew Svetlov
Author-email: [email protected]
License: Apache 2
Location: /nix/store/x5xcb256wikwbh2p443ximbbdn9l7h2h-python3.9-yarl-1.6.3/lib/python3.9/site-packages
Requires: idna, multidict
Required-by:

OS

Nixos x86_64-linux.

Full build/test log: python3.9-aiohttp-3.7.4.log.txt

Related component

Client

Additional context

No response

Code of Conduct

• I agree to follow the aio-libs Code of Conduct

[Dreamsorcerer]

The 3.8 branch is ignoring the errors for the moment. It'll be fixed properly with Python 3.9.8 (out in about 4 weeks I believe).