def METHOD_NAME(self):
    cases = {"name": ("", "name"),
             "name:app": ("", "name:app"),
             "name:app:rel": ("name", "app:rel"),
             "name:app:rel:other": ("name", "app:rel:other"),
             }
    for name, case in cases.items():
        self.assertEqual(maybe_parse_offer_url_source(name), case)