* result is {@link Double#NaN}. If it contains {@link Double#POSITIVE_INFINITY} and finite values
   * only or {@link Double#POSITIVE_INFINITY} only, the result is {@link Double#POSITIVE_INFINITY}.
   * If it contains {@link Double#NEGATIVE_INFINITY} and finite values only or {@link
   * Double#NEGATIVE_INFINITY} only, the result is {@link Double#NEGATIVE_INFINITY}.
   *

   * result is {@link Double#NaN}. If it contains {@link Double#POSITIVE_INFINITY} and finite values
   * only or {@link Double#POSITIVE_INFINITY} only, the result is {@link Double#POSITIVE_INFINITY}.
   * If it contains {@link Double#NEGATIVE_INFINITY} and finite values only or {@link
   * Double#NEGATIVE_INFINITY} only, the result is {@link Double#NEGATIVE_INFINITY}.
   *

    if (lower == NEGATIVE_INFINITY) {
      if (upper == POSITIVE_INFINITY) {
        // Return NaN when lower == NEGATIVE_INFINITY and upper == POSITIVE_INFINITY:
        return NaN;
      }
      // Return NEGATIVE_INFINITY when NEGATIVE_INFINITY == lower <= upper < POSITIVE_INFINITY:
      return NEGATIVE_INFINITY;
    }
    if (upper == POSITIVE_INFINITY) {

      assertThrows(
          ArithmeticException.class, () -> DoubleMath.roundToInt(Double.POSITIVE_INFINITY, mode));
      assertThrows(
          ArithmeticException.class, () -> DoubleMath.roundToInt(Double.NEGATIVE_INFINITY, mode));
    }
  }

  @GwtIncompatible // DoubleMath.roundToLong(double, RoundingMode)
  public void testRoundIntegralDoubleToLong() {
    for (double d : INTEGRAL_DOUBLE_CANDIDATES) {

        .containsExactly(
            0, NEGATIVE_INFINITY,
            1, NEGATIVE_INFINITY, // interpolating between NEGATIVE_INFINITY and 1.0
            2, 1.0,
            8, 4.0,
            9, 4.5,
            10, 5.0);
  }

  public void testScale_index_compute_doubleCollection_negativeInfinity() {
    // interpolating between NEGATIVE_INFINITY and 1.0

        .containsExactly(
            0, NEGATIVE_INFINITY,
            1, NEGATIVE_INFINITY, // interpolating between NEGATIVE_INFINITY and 1.0
            2, 1.0,
            8, 4.0,
            9, 4.5,
            10, 5.0);
  }

  public void testScale_index_compute_doubleCollection_negativeInfinity() {
    // interpolating between NEGATIVE_INFINITY and 1.0

   * times, due to numerical errors.
   *
   * <h3>Non-finite values</h3>
   *
   * <p>If the dataset contains any non-finite values ({@link Double#POSITIVE_INFINITY}, {@link
   * Double#NEGATIVE_INFINITY}, or {@link Double#NaN}) then the result is {@link Double#NaN}.
   *
   * @throws IllegalStateException if the dataset is empty
   */
  public double populationCovariance() {
    checkState(count() != 0);

   * times, due to numerical errors.
   *
   * <h3>Non-finite values</h3>
   *
   * <p>If the dataset contains any non-finite values ({@link Double#POSITIVE_INFINITY}, {@link
   * Double#NEGATIVE_INFINITY}, or {@link Double#NaN}) then the result is {@link Double#NaN}.
   *
   * @throws IllegalStateException if the dataset is empty
   */
  public double populationCovariance() {
    checkState(count() != 0);

    new RoundToDoubleTester(minDoubleAsBigDecimal)
        .setExpectation(-Double.MAX_VALUE, DOWN, CEILING, HALF_EVEN, HALF_UP, HALF_DOWN)
        .setExpectation(Double.NEGATIVE_INFINITY, UP, FLOOR)
        .roundUnnecessaryShouldThrow()
        .test();
  }

  public void testRoundToDouble_negativeWayTooBig() {
    BigDecimal bi = BigDecimal.valueOf(2).pow(2 * Double.MAX_EXPONENT).negate();

  static final ImmutableSet<Double> FRACTIONAL_DOUBLE_CANDIDATES;
  static final Iterable<Double> INFINITIES =
      Doubles.asList(Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY);
  static final Iterable<Double> FINITE_DOUBLE_CANDIDATES;
  static final Iterable<Double> POSITIVE_FINITE_DOUBLE_CANDIDATES;
  static final Iterable<Double> ALL_DOUBLE_CANDIDATES;