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();

      assertThat(DoubleUtils.ensureNonNegative(-positiveValue)).isEqualTo(0.0);
    }
    assertThat(DoubleUtils.ensureNonNegative(Double.POSITIVE_INFINITY)).isPositiveInfinity();
    assertThat(DoubleUtils.ensureNonNegative(Double.NEGATIVE_INFINITY)).isEqualTo(0.0);
    assertThrows(IllegalArgumentException.class, () -> DoubleUtils.ensureNonNegative(Double.NaN));
  }

      assertThat(DoubleUtils.ensureNonNegative(-positiveValue)).isEqualTo(0.0);
    }
    assertThat(DoubleUtils.ensureNonNegative(Double.POSITIVE_INFINITY)).isPositiveInfinity();
    assertThat(DoubleUtils.ensureNonNegative(Double.NEGATIVE_INFINITY)).isEqualTo(0.0);
    assertThrows(IllegalArgumentException.class, () -> DoubleUtils.ensureNonNegative(Double.NaN));
  }

      } 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) {

    // interpolating between 5.0 and POSITIVE_INFINITY
    assertThat(Quantiles.scale(10).index(9).compute(ONE_TO_FIVE_AND_POSITIVE_INFINITY))
        .isPositiveInfinity();
  }

  public void testScale_indexes_varargs_compute_doubleCollection_negativeInfinity() {
    assertThat(
            Quantiles.scale(10)
                .indexes(0, 1, 2, 8, 9, 10)