return "forward";
      }

      @Override
      protected String doBackward(String string) {
        return "backward";
      }
    };
  }

  public void testSerialization_identity() {
    Converter<String, String> identityConverter = Converter.identity();
    SerializableTester.reserializeAndAssert(identityConverter);
  }

  public void testSerialization_reverse() {