3.4.0: testing fails with some pytest plugins installed

[mtelka]

I found that when pytest-xdist is tested with pytest-console-scripts or pytest-checkdocs or pytest-randomly installed and disabled using -p no:XXX set in PYTEST_ADDOPTS environment variable then the testing fails:

============================= test session starts ==============================
platform sunos5 -- Python 3.9.16, pytest-7.4.3, pluggy-1.3.0 -- $(BUILD_DIR)/.tox/py39/bin/python
cachedir: .tox/py39/.pytest_cache
rootdir: $(BUILD_DIR)
configfile: tox.ini
testpaths: testing
plugins: xdist-3.4.0
collecting ... collected 203 items

testing/acceptance_test.py::TestDistribution::test_n1_pass PASSED        [  0%]
testing/acceptance_test.py::TestDistribution::test_n1_fail FAILED        [  0%]

=================================== FAILURES ===================================
________________________ TestDistribution.test_n1_fail _________________________

self = <acceptance_test.TestDistribution object at 0x7fffadcb2760>
pytester = <Pytester PosixPath('/tmp/pytest-of-marcel/pytest-79/test_n1_fail0')>

    def test_n1_fail(self, pytester: pytest.Pytester) -> None:
        p1 = pytester.makepyfile(
            """
            def test_fail():
                assert 0
        """
        )
        result = pytester.runpytest(p1, "-n1")
>       assert result.ret == 1
E       assert <ExitCode.USAGE_ERROR: 4> == 1
E        +  where <ExitCode.USAGE_ERROR: 4> = <RunResult ret=ExitCode.USAGE_ERROR len(stdout.lines)=0 len(stderr.lines)=5 duration=0.03s>.ret

$(BUILD_DIR)/testing/acceptance_test.py:32: AssertionError
----------------------------- Captured stderr call -----------------------------
ERROR: usage: __main__.py [options] [file_or_dir] [file_or_dir] [...]
__main__.py: error: unrecognized arguments: -n1
  inifile: None
  rootdir: /tmp/pytest-of-marcel/pytest-79/test_n1_fail0

=========================== short test summary info ============================
FAILED testing/acceptance_test.py::TestDistribution::test_n1_fail - assert <E...
!!!!!!!!!!!!!!!!!!!!!!!!!! stopping after 1 failures !!!!!!!!!!!!!!!!!!!!!!!!!!!

Interestingly, testing pass when there are some other pytest plugins installed, for example pytest-black or pytest-mypy.

See also: https://github.com/kvas-it/pytest-console-scripts/issues/85

[nicoddemus]

Hi @mtelka,

That error looks a bit strange to me, why would that test (and only that test) fail to load pytest-xdist's -n option? Weird. The header does show that only xdist is active...

[mtelka]

To avoid this issue we should simply do not install (or load) pytest plugins that are not needed to run tests for pytest-xdist.