def METHOD_NAME(self):
    fake_id = FAKE_USER_IDENTITY_RESOURCE_ID
    user_assigned = set(fake_id)
    ns = Namespace(user_assigned=user_assigned, system_assigned=None)
    with self.assertRaises(InvalidArgumentValueError) as context:
        validate_app_identity_remove_or_warning(ns)
    self.assertTrue("Parameter value for \"user-assigned\" should be empty or a list of space-separated managed identity resource ID." in str(context.exception))