def test_no_ini(pytester: Pytester, file_structure) -> None:
    """If no ini file, test should error."""
    result = pytester.runpytest("test_foo.py")
    assert result.ret == pytest.ExitCode.INTERRUPTED
    result.assert_outcomes(errors=1)
    expected_error = "E   ModuleNotFoundError: No module named 'foo'"
    result.stdout.fnmatch_lines([expected_error])
If no ini file, test should error.
testing/test_python_path.py