public void testEnsureNonNegative() {
    assertThat(DoubleUtils.ensureNonNegative(0.0)).isEqualTo(0.0);
    for (double positiveValue : POSITIVE_FINITE_DOUBLE_CANDIDATES) {
      assertThat(DoubleUtils.ensureNonNegative(positiveValue)).isEqualTo(positiveValue);
      assertThat(DoubleUtils.ensureNonNegative(-positiveValue)).isEqualTo(0.0);
    }
    assertThat(DoubleUtils.ensureNonNegative(Double.POSITIVE_INFINITY)).isPositiveInfinity();

     */
    bits |= x.signum() & SIGN_MASK;
    return longBitsToDouble(bits);
  }

  /** Returns its argument if it is non-negative, zero if it is negative. */
  static double ensureNonNegative(double value) {
    checkArgument(!isNaN(value));
    return max(value, 0.0);
  }

  @VisibleForTesting static final long ONE_BITS = 0x3ff0000000000000L;

     */
    bits |= x.signum() & SIGN_MASK;
    return longBitsToDouble(bits);
  }

  /** Returns its argument if it is non-negative, zero if it is negative. */
  static double ensureNonNegative(double value) {
    checkArgument(!isNaN(value));
    return max(value, 0.0);
  }

  @VisibleForTesting static final long ONE_BITS = 0x3ff0000000000000L;