Add test coverage for compiled regex patterns in pytest.raises()

[vicky-dx]

Summary

This PR adds test coverage for using compiled regex patterns (re.Pattern objects) with the match parameter in pytest.raises(). While this functionality already works, it wasn't explicitly tested.

Changes

• Added test_raises_match_compiled_regex() in testing/python/raises.py
• Tests three scenarios:
  1. Compiled regex pattern that matches
  2. Compiled regex pattern that doesn't match (verifies error message)
  3. Compiled regex with flags (e.g., re.IGNORECASE)

Checklist

• Include new tests or update existing tests when applicable.
• Allow maintainers to push and squash when merging my commits.
• Create a new changelog file in the changelog folder (will add after PR number is assigned)
• Add yourself to AUTHORS in alphabetical order.

Notes

This is a test coverage improvement that ensures the existing functionality for compiled regex patterns remains stable in future releases.

[Pierre-Sassoulas]

Hey @vicky-dx, thank you for working on pytest. I think it wasn't actually tested the coverage metric would have gone up. How did you determine it wasn't covered ?

[jakkdl]

I think the coverage is coming from tests with RaisesGroup (and ~all of the regex handling is in the AbstractRaises base class)

pytest/testing/python/raises_group.py

Lines 1200 to 1210 in 980bb5c

	def test_raisesexc_tostring() -> None:
	assert str(RaisesExc(ValueError)) == "RaisesExc(ValueError)"
	assert str(RaisesExc(match="[a-z]")) == "RaisesExc(match='[a-z]')"
	pattern_no_flags = re.compile(r"noflag", 0)
	assert str(RaisesExc(match=pattern_no_flags)) == "RaisesExc(match='noflag')"
	pattern_flags = re.compile(r"noflag", re.IGNORECASE)
	assert str(RaisesExc(match=pattern_flags)) == f"RaisesExc(match={pattern_flags!r})"
	assert (
	str(RaisesExc(ValueError, match="re", check=bool))
	== f"RaisesExc(ValueError, match='re', check={bool!r})"
	)

but that code is not doing end-to-end testing with compiled regexes, so seems fair enough to add tests that do it.

FTR I double-checked and raises.py does have 100% coverage across the file.

[The-Compiler]

I think @vicky-dx might have meant "test coverage" in the (more loose) sense of the term, not in the sense of "number goes up".

Seems sensible to me!