@NullMarked
@GwtCompatible
public class BigIntegerMathTest extends TestCase {
  public void testCeilingPowerOfTwo() {
    for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
      BigInteger result = BigIntegerMath.ceilingPowerOfTwo(x);
      assertTrue(BigIntegerMath.isPowerOfTwo(result));
      assertTrue(result.compareTo(x) >= 0);
      assertTrue(result.compareTo(x.add(x)) < 0);
    }
  }

  public void testFloorPowerOfTwo() {

    for (int x : POSITIVE_INTEGER_CANDIDATES) {
      BigInteger expectedResult = BigIntegerMath.ceilingPowerOfTwo(BigInteger.valueOf(x));
      if (fitsInInt(expectedResult)) {
        assertEquals(expectedResult.intValue(), IntMath.ceilingPowerOfTwo(x));
      } else {
        assertThrows(ArithmeticException.class, () -> IntMath.ceilingPowerOfTwo(x));
      }
    }
  }

  public void testFloorPowerOfTwo() {

    for (long x : POSITIVE_LONG_CANDIDATES) {
      BigInteger expectedResult = BigIntegerMath.ceilingPowerOfTwo(BigInteger.valueOf(x));
      if (fitsInLong(expectedResult)) {
        assertEquals(expectedResult.longValue(), LongMath.ceilingPowerOfTwo(x));
      } else {
        assertThrows(ArithmeticException.class, () -> LongMath.ceilingPowerOfTwo(x));
      }
    }
  }

  public void testFloorPowerOfTwo() {

   * {@code BigInteger.valueOf(2).pow(log2(x, CEILING))}.
   *
   * @throws IllegalArgumentException if {@code x <= 0}
   * @since 20.0
   */
  public static BigInteger ceilingPowerOfTwo(BigInteger x) {
    return BigInteger.ZERO.setBit(log2(x, CEILING));
  }

  /**
   * Returns the largest power of two less than or equal to {@code x}. This is equivalent to {@code

   *     long}, i.e. when {@code x > 2^62}
   * @since 20.0
   */
  public static long ceilingPowerOfTwo(long x) {
    checkPositive("x", x);
    if (x > MAX_SIGNED_POWER_OF_TWO) {
      throw new ArithmeticException("ceilingPowerOfTwo(" + x + ") is not representable as a long");
    }
    return 1L << -Long.numberOfLeadingZeros(x - 1);
  }

  /**