assertEquals(expected.toBigInteger(), DoubleMath.roundToBigInteger(d, UNNECESSARY));
    }
  }

  @GwtIncompatible // DoubleMath.roundToBigInteger(double, RoundingMode)
  public void testRoundExactFractionalDoubleToBigIntegerFails() {
    for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
      assertThrows(ArithmeticException.class, () -> DoubleMath.roundToBigInteger(d, UNNECESSARY));
    }
  }

      assertEquals(expected.toBigInteger(), DoubleMath.roundToBigInteger(d, UNNECESSARY));
    }
  }

  @GwtIncompatible // DoubleMath.roundToBigInteger(double, RoundingMode)
  public void testRoundExactFractionalDoubleToBigIntegerFails() {
    for (double d : FRACTIONAL_DOUBLE_CANDIDATES) {
      assertThrows(ArithmeticException.class, () -> DoubleMath.roundToBigInteger(d, UNNECESSARY));
    }
  }

    } while (sqrt1.compareTo(sqrt0) < 0);
    return sqrt0;
  }

  @GwtIncompatible // TODO
  private static BigInteger sqrtApproxWithDoubles(BigInteger x) {
    return DoubleMath.roundToBigInteger(Math.sqrt(DoubleUtils.bigToDouble(x)), HALF_EVEN);
  }

  /**
   * Returns {@code x}, rounded to a {@code double} with the specified rounding mode. If {@code x}