assertTrue(BigIntegerMath.isPowerOfTwo(result));
      assertThat(result).isAtLeast(x);
      assertThat(result).isLessThan(x.add(x));
    }
  }

  public void testFloorPowerOfTwo() {
    for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
      BigInteger result = BigIntegerMath.floorPowerOfTwo(x);
      assertTrue(BigIntegerMath.isPowerOfTwo(result));
      assertThat(result).isAtMost(x);