public LongValue increment(long increment) {
    this.value += increment;
    this.set = true;
    return this;
  }
@Test
  public void multiple_calls_to_increment_LongVariationValue_increments_by_the_value_of_the_arg() {
    LongValue target = new LongValue()
      .increment(new LongValue().increment(35L))
      .increment(new LongValue().increment(10L));

    verifySetVariationValue(target, 45L);
  }