Python 3.8 test_static_resource failure: TypeError: issubclass() arg 1 must be a class

[hroncok]

Hello. I wish to run tests on Python 3.8, but I needed to fight some problems. This is how I was able to run them on current master:

diff --git a/pytest.ini b/pytest.ini
deleted file mode 100644
index e62899b..0000000
--- a/pytest.ini
+++ /dev/null
@@ -1,3 +0,0 @@
-[pytest]
-filterwarnings=
-    error
diff --git a/tox.ini b/tox.ini
index 9668d37..bb10832 100644
--- a/tox.ini
+++ b/tox.ini
@@ -5,6 +5,7 @@ envlist = py34, py35, check
 commands = {envpython} setup.py test
 deps =
     pytest
+    pytest-aiohttp
 
 [testenv:check]
 deps =

$ tox -e py38

And this is the error I get:

============================= test session starts ==============================
platform linux -- Python 3.8.0, pytest-5.2.2, py-1.8.0, pluggy-0.13.0
cachedir: .tox/py38/.pytest_cache
rootdir: /home/churchyard/Dokumenty/aiohttp-cors, inifile: tox.ini, testpaths: aiohttp_cors, tests
plugins: cov-2.8.1, pylint-0.14.1, aiohttp-0.3.0
collected 99 items

tests/doc/test_basic_usage.py ..                                         [  2%]
tests/integration/test_main.py ......................................... [ 43%]
.............................                                            [ 72%]
tests/integration/test_real_browser.py ssssss                            [ 78%]
tests/unit/test___about__.py .                                           [ 79%]
tests/unit/test_cors_config.py ....F...                                  [ 87%]
tests/unit/test_mixin.py .....                                           [ 92%]
tests/unit/test_preflight_handler.py .                                   [ 93%]
tests/unit/test_resource_options.py ...                                  [ 96%]
tests/unit/test_urldispatcher_router_adapter.py ...                      [100%]

=================================== FAILURES ===================================
_____________________________ test_static_resource _____________________________

app = <Application 0x7f735d3d6100>
cors = <aiohttp_cors.cors_config.CorsConfig object at 0x7f735d35c400>

    def test_static_resource(app, cors):
        """Test adding static resource."""
        assert len(app.router.keys()) == 0
        app.router.add_static(
            "/file", "/", name="dynamic_named_route")
        assert len(app.router.keys()) == 1
        for resource in list(app.router.resources()):
>           if issubclass(resource, web.StaticResource):

tests/unit/test_cors_config.py:106: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

cls = <class 'aiohttp.web_urldispatcher.StaticResource'>
subclass = <StaticResource 'dynamic_named_route' /file -> PosixPath('/')>

    def __subclasscheck__(cls, subclass):
        """Override for issubclass(subclass, cls)."""
>       return _abc_subclasscheck(cls, subclass)
E       TypeError: issubclass() arg 1 must be a class

.tox/py38/lib64/python3.8/abc.py:102: TypeError
=============================== warnings summary ===============================
tests/unit/test_cors_config.py:33
  /home/churchyard/Dokumenty/aiohttp-cors/tests/unit/test_cors_config.py:33: DeprecationWarning: "@coroutine" decorator is deprecated since Python 3.8, use "async def" instead
    def get(self):

tests/integration/test_main.py::test_dummy_setup[pyloop]
  /home/churchyard/Dokumenty/aiohttp-cors/.tox/py38/lib/python3.8/site-packages/aiohttp/web_server.py:53: DeprecationWarning: The loop argument is deprecated since Python 3.8, and scheduled for removal in Python 3.10.
    await asyncio.gather(*coros, loop=self._loop)

-- Docs: https://docs.pytest.org/en/latest/warnings.html
============= 1 failed, 92 passed, 6 skipped, 2 warnings in 5.91s ==============