assertThat(result.pow(2)).isAtMost(x);
        assertThat(result.add(ONE).pow(2)).isGreaterThan(x);
      }
    }
  }

  @GwtIncompatible // TODO
  public void testSqrtCeiling() {
    for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
      for (RoundingMode mode : asList(CEILING, UP)) {
        BigInteger result = BigIntegerMath.sqrt(x, mode);
        assertThat(result).isGreaterThan(ZERO);