.of(LONG_MANY_VALUES_MEAN);
    assertThat(longManyValuesAccumulatorByAddAllVarargs.mean())
        .isWithin(ALLOWED_ERROR * LONG_MANY_VALUES_MEAN)
        .of(LONG_MANY_VALUES_MEAN);
  }

  public void testSum() {
    assertThat(emptyAccumulator.sum()).isEqualTo(0.0);
    assertThat(emptyAccumulatorByAddAllEmptyIterable.sum()).isEqualTo(0.0);
    assertThat(emptyAccumulatorByAddAllEmptyStats.sum()).isEqualTo(0.0);

    assertThat(Enums.getIfPresent(TestEnum.class, "HONDA")).isPresent();
    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).isPresent();

    assertThat(Enums.getIfPresent(TestEnum.class, "CHEETO")).hasValue(TestEnum.CHEETO);
    assertThat(Enums.getIfPresent(TestEnum.class, "HONDA")).hasValue(TestEnum.HONDA);
    assertThat(Enums.getIfPresent(TestEnum.class, "POODLE")).hasValue(TestEnum.POODLE);
  }