Number of tests fail with pytest6

[mcepl]

When building pytest-parallel package for openSUSE/Tumbleweed we found out that number of tests fail with pytest6 (without respect whether we use python 3.6 or 3.8). We had to limit ourselves to pytest5 and then the test suite passes without problems.

[   52s] =========================== short test summary info ============================
[   52s] ERROR tests/test_general.py::test_environ_shim[cli_args2] - AssertionError
[   52s] ERROR tests/test_general.py::test_skip_markers[cli_args0] - AssertionError
[   52s] ERROR tests/test_general.py::test_skip_markers[cli_args1] - AssertionError
[   52s] ERROR tests/test_general.py::test_skip_markers[cli_args2] - AssertionError
[   52s] ERROR tests/test_general.py::test_skipif_markers[cli_args0] - AssertionError
[   52s] ERROR tests/test_general.py::test_skipif_markers[cli_args1] - AssertionError
[   52s] ERROR tests/test_general.py::test_skipif_markers[cli_args2] - AssertionError
[   52s] ERROR tests/test_general.py::test_custom_markers[cli_args0] - AssertionError
[   52s] ERROR tests/test_general.py::test_custom_markers[cli_args1] - AssertionError
[   52s] ERROR tests/test_general.py::test_custom_markers[cli_args2] - AssertionError
[   52s] ERROR tests/test_general.py::test_multiple_failures[cli_args0] - AssertionError
[   52s] ERROR tests/test_general.py::test_multiple_failures[cli_args1] - AssertionError
[   52s] ERROR tests/test_general.py::test_multiple_failures[cli_args2] - AssertionError
[   52s] ERROR tests/test_general.py::test_pytest_html[cli_args0] - AssertionError
[   52s] ERROR tests/test_general.py::test_pytest_html[cli_args1] - AssertionError
[   52s] ERROR tests/test_general.py::test_pytest_html[cli_args2] - AssertionError
[   52s] ERROR tests/test_general.py::test_collection_error[cli_args0] - AssertionError
[   52s] ERROR tests/test_general.py::test_collection_error[cli_args1] - AssertionError
[   52s] ERROR tests/test_general.py::test_collection_error[cli_args2] - AssertionError
[   52s] ERROR tests/test_general.py::test_collection_collectonly[cli_args0] - Asserti...
[   52s] ERROR tests/test_general.py::test_collection_collectonly[cli_args1] - Asserti...
[   52s] ERROR tests/test_general.py::test_collection_collectonly[cli_args2] - Asserti...
[   52s] ======================== 8 passed, 22 errors in 17.99s =========================

Complete build log with details of used packages, their versions, and steps taken for building the package.

[mcepl]

Specifically, one such error looks like this:

[   52s] ___________ ERROR at setup of test_collection_collectonly[cli_args2] ___________
[   52s] 
[   52s] cls = _pytest.runner.CallInfo
[   52s] func = <function call_runtest_hook.<locals>.<lambda> at 0x7f14d7c34c80>
[   52s] when = 'setup'
[   52s] reraise = (<class '_pytest.outcomes.Exit'>, <class 'KeyboardInterrupt'>)
[   52s] 
[   52s]     @classmethod
[   52s]     def from_call(
[   52s]         cls,
[   52s]         func: "Callable[[], TResult]",
[   52s]         when: "Literal['collect', 'setup', 'call', 'teardown']",
[   52s]         reraise: Optional[
[   52s]             Union[Type[BaseException], Tuple[Type[BaseException], ...]]
[   52s]         ] = None,
[   52s]     ) -> "CallInfo[TResult]":
[   52s]         excinfo = None
[   52s]         start = timing.time()
[   52s]         precise_start = timing.perf_counter()
[   52s]         try:
[   52s] >           result: Optional[TResult] = func()
[   52s] 
[   52s] /usr/lib/python3.6/site-packages/_pytest/runner.py:311: 
[   52s] _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
[   52s] /usr/lib/python3.6/site-packages/_pytest/runner.py:255: in <lambda>
[   52s]     lambda: ihook(item=item, **kwds), when=when, reraise=reraise
[   52s] /usr/lib/python3.6/site-packages/pluggy/hooks.py:286: in __call__
[   52s]     return self._hookexec(self, self.get_hookimpls(), kwargs)
[   52s] /usr/lib/python3.6/site-packages/pluggy/manager.py:93: in _hookexec
[   52s]     return self._inner_hookexec(hook, methods, kwargs)
[   52s] /usr/lib/python3.6/site-packages/pluggy/manager.py:87: in <lambda>
[   52s]     firstresult=hook.spec.opts.get("firstresult") if hook.spec else False,
[   52s] /usr/lib/python3.6/site-packages/_pytest/runner.py:150: in pytest_runtest_setup
[   52s]     item.session._setupstate.prepare(item)
[   52s] /usr/lib/python3.6/site-packages/_pytest/runner.py:452: in prepare
[   52s]     raise e
[   52s] /usr/lib/python3.6/site-packages/_pytest/runner.py:449: in prepare
[   52s]     col.setup()
[   52s] /usr/lib/python3.6/site-packages/_pytest/python.py:1647: in setup
[   52s]     self._request._fillfixtures()
[   52s] /usr/lib/python3.6/site-packages/_pytest/fixtures.py:568: in _fillfixtures
[   52s]     item.funcargs[argname] = self.getfixturevalue(argname)
[   52s] /usr/lib/python3.6/site-packages/_pytest/fixtures.py:581: in getfixturevalue
[   52s]     fixturedef = self._get_active_fixturedef(argname)
[   52s] /usr/lib/python3.6/site-packages/_pytest/fixtures.py:601: in _get_active_fixturedef
[   52s]     self._compute_fixture_value(fixturedef)
[   52s] /usr/lib/python3.6/site-packages/_pytest/fixtures.py:687: in _compute_fixture_value
[   52s]     fixturedef.execute(request=subrequest)
[   52s] /usr/lib/python3.6/site-packages/_pytest/fixtures.py:1048: in execute
[   52s]     fixturedef = request._get_active_fixturedef(argname)
[   52s] /usr/lib/python3.6/site-packages/_pytest/fixtures.py:601: in _get_active_fixturedef
[   52s]     self._compute_fixture_value(fixturedef)
[   52s] /usr/lib/python3.6/site-packages/_pytest/fixtures.py:687: in _compute_fixture_value
[   52s]     fixturedef.execute(request=subrequest)
[   52s] _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
[   52s] 
[   52s] self = <FixtureDef argname='pytester' scope='function' baseid=''>
[   52s] request = <SubRequest 'pytester' for <Function test_collection_collectonly[cli_args2]>>
[   52s] 
[   52s]     def execute(self, request: SubRequest) -> _FixtureValue:
[   52s]         # Get required arguments and register our own finish()
[   52s]         # with their finalization.
[   52s]         for argname in self.argnames:
[   52s]             fixturedef = request._get_active_fixturedef(argname)
[   52s]             if argname != "request":
[   52s]                 # PseudoFixtureDef is only for "request".
[   52s] >               assert isinstance(fixturedef, FixtureDef)
[   52s] E               AssertionError
[   52s] 
[   52s] /usr/lib/python3.6/site-packages/_pytest/fixtures.py:1051: AssertionError