public static Optional<Double> computePercent(long hotspotsToReview, long hotspotsReviewed) {
    long total = hotspotsToReview + hotspotsReviewed;
    if (total == 0) {
      return Optional.empty();
    }
    return Optional.of(hotspotsReviewed * 100.0D / total);
  }
@Test
  public void compute_percent() {
    assertThat(computePercent(0, 0)).isEmpty();
    assertThat(computePercent(0, 10)).contains(100.0);
    assertThat(computePercent(1, 3)).contains(75.0);
    assertThat(computePercent(3, 4).get()).isEqualTo(57.14, DOUBLE_OFFSET);
    assertThat(computePercent(10, 10)).contains(50.0);
    assertThat(computePercent(10, 0)).contains(0.0);
  }