for (String invalid : invalidCases) {
      assertFalse(invalid, InternetDomainName.isValid(invalid));
    }
  }

  public void testToString() {
    for (String inputName : SOMEWHERE_UNDER_PS) {
      InternetDomainName domain = InternetDomainName.from(inputName);

      /*
       * We would ordinarily use constants for the expected results, but
       * doing it by derivation allows us to reuse the test case definitions

            `Model.predict_step`.
        *   SavedModel uses its own `Model._saved_model_inputs_spec` attr now
            instead of relying on `Model.inputs` and `Model.input_names`, which
            are no longer set for subclass Models. This attr is set in eager,
            `tf.function`, and graph modes. This gets rid of the need for users