fix for Pytest 8 compat

[mr-c]

In Debian, we upgraded to pytest version 8.1.1+ for the next release.

pytest deprecated the name for the first positional argument to pytest.fail from msg to reason in Pytest 7.0 and removed msg in Pytest 8.0

https://docs.pytest.org/en/7.0.x/reference/reference.html#pytest-fail
https://docs.pytest.org/en/8.0.x/changelog.html#old-deprecations-are-now-errors

[mr-c]

Ideally the minimum version of pytest would be increased to 8.1 and then the following additional change would be included, otherwise mypy will fail its self-checks with Pytest 8.1+

--- mypy.orig/mypy/test/data.py
+++ mypy/mypy/test/data.py
@@ -640,9 +640,7 @@
             # Non-None result means this obj is a test case.
             # The collect method of the returned DataSuiteCollector instance will be called later,
             # with self.obj being obj.
-            return DataSuiteCollector.from_parent(  # type: ignore[no-untyped-call]
-                parent=collector, name=name
-            )
+            return DataSuiteCollector.from_parent(parent=collector, name=name)
     return None

[AlexWaygood]

You could bump our pinned version of pytest by running pip-compile test-requirements.in --allow-unsafe --output-file=test-requirements.txt --strip-extras --upgrade-package pytest

Though if bumping pytest to 8.0+ requires changes to the self-test, then we might want to raise the lower bound specified in requirements.in, actually

[github-actions]

According to mypy_primer, this change doesn't affect type check results on a corpus of open source code. ✅

[JelleZijlstra]

Looks good, just waiting for CI to finish