assertThrows(IllegalStateException.class, () -> EMPTY_STATS_ITERABLE.mean());
    assertThat(ONE_VALUE_STATS.mean()).isWithin(ALLOWED_ERROR).of(ONE_VALUE);
    assertThat(Stats.of(POSITIVE_INFINITY).mean()).isPositiveInfinity();
    assertThat(Stats.of(NEGATIVE_INFINITY).mean()).isNegativeInfinity();
    assertThat(Stats.of(NaN).mean()).isNaN();
    assertThat(TWO_VALUES_STATS.mean()).isWithin(ALLOWED_ERROR).of(TWO_VALUES_MEAN);

    }
  }

  public void testFactorialTooHigh() {
    assertThat(DoubleMath.factorial(DoubleMath.MAX_FACTORIAL + 1)).isPositiveInfinity();
    assertThat(DoubleMath.factorial(DoubleMath.MAX_FACTORIAL + 20)).isPositiveInfinity();
  }

  public void testFactorialNegative() {
    for (int n : NEGATIVE_INTEGER_CANDIDATES) {

      } else if (values.hasAnyPositiveInfinity()) {
        assertWithMessage("mean of " + values).that(mean).isPositiveInfinity();
        assertWithMessage("mean by addAll(Stats) of " + values)
            .that(meanByAddAllStats)
            .isPositiveInfinity();
      } else if (values.hasAnyNegativeInfinity()) {
        assertWithMessage("mean of " + values).that(mean).isNegativeInfinity();

      } else if (values.hasAnyPositiveInfinity()) {
        assertWithMessage("mean of " + values).that(mean).isPositiveInfinity();
        assertWithMessage("mean by addAll(Stats) of " + values)
            .that(meanByAddAllStats)
            .isPositiveInfinity();
      } else if (values.hasAnyNegativeInfinity()) {
        assertWithMessage("mean of " + values).that(mean).isNegativeInfinity();

    }
  }

  public void testFactorialTooHigh() {
    assertThat(DoubleMath.factorial(DoubleMath.MAX_FACTORIAL + 1)).isPositiveInfinity();
    assertThat(DoubleMath.factorial(DoubleMath.MAX_FACTORIAL + 20)).isPositiveInfinity();
  }

  public void testFactorialNegative() {
    for (int n : NEGATIVE_INTEGER_CANDIDATES) {