def assertMatches(self, matcher: TMatcher, filepath: str, matches: bool) -> None:
        """The `matcher` should agree with `matches` about `filepath`."""
        canonical = files.canonical_filename(filepath)
        msg = f"File {filepath} should have matched as {matches}"
        assert matches == matcher.match(canonical), msg
The `matcher` should agree with `matches` about `filepath`.
tests/test_files.py