return "backward";
      }
    };
  }

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

  public void testSerialization_reverse() {
    Converter<Long, String> reverseConverter = Longs.stringConverter().reverse();