assertTrue(BigIntegerMath.isPowerOfTwo(result));
      assertTrue(result.compareTo(x) >= 0);
      assertTrue(result.compareTo(x.add(x)) < 0);
    }
  }

  public void testFloorPowerOfTwo() {
    for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
      BigInteger result = BigIntegerMath.floorPowerOfTwo(x);
      assertTrue(BigIntegerMath.isPowerOfTwo(result));
      assertTrue(result.compareTo(x) <= 0);