The signature of pytest.skip is:

skip(msg[, allow_module_level=False])

but the signature of pytest.xfail is:

xfail(reason='')

Marks (pytest.mark.skip, pytest.mark.skipif and pytest.mark.xfail) use reason too:

pytest.mark.skipif(condition, *, reason=None)
pytest.mark.xfail(condition=None, *, reason=None, raises=None, run=True, strict=False)¶
pytest.mark.skipif(condition, *, reason=None)¶

Note that pytest.fail uses msg:

fail(msg='', pytrace=True)

but at least from an user perspective, skip is probably closer to xfail and mark.skip / mark.skipif / mark.xfail.

Should we rename the msg argument for pytest.skip to reason for consistency (with a deprecation for the old name), or isn't that worth the trouble?

Thanks to Francesco Casalegno for reporting this in the pytest training I gave at Europython 2021 today!