Test failures with Python 3.10.0a7

Hello, we see some test failures due to different reprs in Python 3.10.0a7.

This is on branch main, @ 9653a0e9f47ad2ae5135a974db52ddeb5bfcf5d9.

Fedora Linux 33, 34 or 35.

$ tox -e py310
... installs deps, kill ...
$ .tox/py310/bin/pip install -U https://github.com/benjaminp/six/archive/refs/heads/master.zip
$ tox -e py310 -- testing/test_pytester.py testing/python/metafunc.py
py310 inst-nodeps: /home/churchyard/Dokumenty/RedHat/pytest/.tox/.tmp/package/3/pytest-6.3.0.dev355+g9653a0e9f.tar.gz
py310 installed: argcomplete==1.12.2,attrs==20.3.0,certifi==2020.12.5,chardet==4.0.0,elementpath==2.2.1,hypothesis==6.9.1,idna==2.10,iniconfig==1.1.1,mock==4.0.3,nose==1.3.7,packaging==20.9,pluggy==0.13.1,py==1.10.0,Pygments==2.8.1,pyparsing==2.4.7,pytest @ file:///home/churchyard/Dokumenty/RedHat/pytest/.tox/.tmp/package/3/pytest-6.3.0.dev355%2Bg9653a0e9f.tar.gz,requests==2.25.1,six @ https://github.com/benjaminp/six/archive/refs/heads/master.zip,sortedcontainers==2.3.0,toml==0.10.2,urllib3==1.26.4,xmlschema==1.6.1
py310 run-test-pre: PYTHONHASHSEED='3484571371'
py310 run-test: commands[0] | pytest testing/test_pytester.py testing/python/metafunc.py
============================= test session starts ==============================
platform linux -- Python 3.10.0a7, pytest-6.3.0.dev355+g9653a0e9f, py-1.10.0, pluggy-0.13.1
cachedir: .tox/py310/.pytest_cache
rootdir: /home/churchyard/Dokumenty/RedHat/pytest, configfile: pyproject.toml
plugins: hypothesis-6.9.1
collected 155 items

testing/test_pytester.py ...................F.                           [ 13%]
testing/python/metafunc.py .......................F.................     [ 40%]
testing/test_pytester.py x...........................                    [ 58%]
testing/python/metafunc.py ............................................. [ 87%]
...............                                                          [ 96%]
testing/test_pytester.py ....s                                           [100%]

=================================== FAILURES ===================================
_____________________________ test_run_result_repr _____________________________

    def test_run_result_repr() -> None:
        outlines = ["some", "normal", "output"]
        errlines = ["some", "nasty", "errors", "happened"]
    
        # known exit code
        r = pytester_mod.RunResult(1, outlines, errlines, duration=0.5)
>       assert (
            repr(r) == "<RunResult ret=ExitCode.TESTS_FAILED len(stdout.lines)=3"
            " len(stderr.lines)=4 duration=0.50s>"
        )
E       AssertionError: assert '<RunResult r...ration=0.50s>' == '<RunResult r...ration=0.50s>'
E         - <RunResult ret=ExitCode.TESTS_FAILED len(stdout.lines)=3 len(stderr.lines)=4 duration=0.50s>
E         ?                ---------
E         + <RunResult ret=TESTS_FAILED len(stdout.lines)=3 len(stderr.lines)=4 duration=0.50s>

testing/test_pytester.py:747: AssertionError
________________________ TestMetafunc.test_idmaker_enum ________________________

self = <metafunc.TestMetafunc object at 0x7f666fa0a710>

    def test_idmaker_enum(self) -> None:
        enum = pytest.importorskip("enum")
        e = enum.Enum("Foo", "one, two")
        result = idmaker(("a", "b"), [pytest.param(e.one, e.two)])
>       assert result == ["Foo.one-Foo.two"]
E       AssertionError: assert ['one-two'] == ['Foo.one-Foo.two']
E         At index 0 diff: 'one-two' != 'Foo.one-Foo.two'
E         Use -v to get the full diff

testing/python/metafunc.py:451: AssertionError
=========================== short test summary info ============================
FAILED testing/test_pytester.py::test_run_result_repr - AssertionError: asser...
FAILED testing/python/metafunc.py::TestMetafunc::test_idmaker_enum - Assertio...
============= 2 failed, 151 passed, 1 skipped, 1 xfailed in 5.27s ==============
ERROR: InvocationError for command /home/churchyard/Dokumenty/RedHat/pytest/.tox/py310/bin/pytest testing/test_pytester.py testing/python/metafunc.py (exited with code 1)
___________________________________ summary ____________________________________
ERROR:   py310: commands failed

The first problem is here:

https://github.com/pytest-dev/pytest/blob/9653a0e9f47ad2ae5135a974db52ddeb5bfcf5d9/testing/test_pytester.py#L748

The second is here:

https://github.com/pytest-dev/pytest/blob/9653a0e9f47ad2ae5135a974db52ddeb5bfcf5d9/testing/python/metafunc.py#L451

This mgiht be related:

https://docs.python.org/3.10/whatsnew/3.10.html#enum says:

Enum repr() now returns enum_name.member_name and str() now returns member_name. Stdlib enums available as module constants have a repr() of module_name.member_name. (Contributed by Ethan Furman in bpo-40066.)

Package          Version
---------------- -----------------------
argcomplete      1.12.2
attrs            20.3.0
certifi          2020.12.5
chardet          4.0.0
elementpath      2.2.1
hypothesis       6.9.1
idna             2.10
iniconfig        1.1.1
mock             4.0.3
nose             1.3.7
packaging        20.9
pip              21.0.1
pluggy           0.13.1
py               1.10.0
Pygments         2.8.1
pyparsing        2.4.7
pytest           6.3.0.dev355+g9653a0e9f
requests         2.25.1
setuptools       53.0.0
six              1.15.0
sortedcontainers 2.3.0
toml             0.10.2
urllib3          1.26.4
wheel            0.36.2
xmlschema        1.6.1

[RonnyPfannschmidt]

If all we need is a custom repr on the enum let’s go for it

[nicoddemus]

Fixed by #8540.