new EqualsTester()
        .addEqualityGroup(STR_TO_LONG, STR_TO_LONG.reverse().reverse())
        .addEqualityGroup(STR_TO_LONG.reverse(), STR_TO_LONG.reverse())
        .testEquals();
  }

  public void testReverseReverse() {
    Converter<String, Long> converter = STR_TO_LONG;
    assertEquals(converter, converter.reverse().reverse());
  }

  public void testApply() {
    assertEquals(LONG_VAL, STR_TO_LONG.apply(STR_VAL));