def assert_mapped(self, aliases: PathAliases, inp: str, out: str) -> None:
        """Assert that `inp` mapped through `aliases` produces `out`.

        If the aliases are not relative, then `out` is canonicalized first,
        since aliases produce canonicalized paths by default.

        """
        mapped = aliases.map(inp, exists=lambda p: True)
        if aliases.relative:
            expected = out
        else:
            expected = files.canonical_filename(out)
        assert mapped == expected
Assert that `inp` mapped through `aliases` produces `out`.

        If the aliases are not relative, then `out` is canonicalized first,
        since aliases produce canonicalized paths by default.

        
tests/test_files.py