.roundUnnecessaryShouldThrow()
        .test();
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testRoundToDouble_twoToThe54PlusOne() {
    double twoToThe54 = Math.pow(2, 54);
    // the representable doubles are 2^54 and 2^54 + 4
    // 2^54+1 is less than halfway between, so HALF_DOWN and HALF_UP will both go down.
    new RoundToDoubleTester(BigInteger.valueOf((1L << 54) + 1))

    assertThat(Chars.constrainToRange((char) 1, (char) 3, (char) 5)).isEqualTo((char) 3);
    assertThat(Chars.constrainToRange((char) 255, (char) 250, (char) 254)).isEqualTo((char) 254);
    assertThat(Chars.constrainToRange((char) 5, (char) 2, (char) 2)).isEqualTo((char) 2);
    assertThrows(
        IllegalArgumentException.class, () -> Chars.constrainToRange((char) 1, (char) 3, (char) 2));
  }

    if (log2 < Double.MAX_EXPONENT) {
      sqrt0 = sqrtApproxWithDoubles(x);
    } else {
      int shift = (log2 - DoubleUtils.SIGNIFICAND_BITS) & ~1; // even!
      /*
       * We have that x / 2^shift < 2^54. Our initial approximation to sqrtFloor(x) will be
       * 2^(shift/2) * sqrtApproxWithDoubles(x / 2^shift).
       */
      sqrt0 = sqrtApproxWithDoubles(x.shiftRight(shift)).shiftLeft(shift >> 1);
    }

    checkInitialCapacity(2, 0, 1);
    checkInitialCapacity(2, 1, 1);
    checkInitialCapacity(2, 2, 1);
    checkInitialCapacity(2, 3, 2);
    checkInitialCapacity(2, 4, 2);
    checkInitialCapacity(2, 5, 4);
    checkInitialCapacity(2, 6, 4);
    checkInitialCapacity(2, 7, 4);
    checkInitialCapacity(2, 8, 4);

    checkInitialCapacity(4, 0, 1);
    checkInitialCapacity(4, 1, 1);