'Those values are valid on some Python versions (and systems?).
On others, they raise a DeprecationWarning because of an invalid
escape. This tests makes sure this gets translated to a
ValidationError.'

@pytest.mark.parametrize('val', ['foo\\Xbar', 'foo\\Cbar'])
def test_validate_maybe_valid(self, klass, val):

    try:
        klass().validate(val)
    except configexc.ValidationError:
        pass
