public LongValue increment(long increment) {
    this.value += increment;
    this.set = true;
    return this;
  }
@Test
  public void increment_LongVariationValue_increments_by_the_value_of_the_arg() {
    LongValue source = new LongValue().increment(10L);
    LongValue target = new LongValue().increment(source);

    verifySetVariationValue(target, 10L);
  }