}

  public void testIsPowerOfTwo() {
    for (BigInteger x : ALL_BIGINTEGER_CANDIDATES) {
      // Checks for a single bit set.
      boolean expected = x.signum() > 0 & x.and(x.subtract(ONE)).equals(ZERO);
      assertEquals(expected, BigIntegerMath.isPowerOfTwo(x));
    }
  }

  public void testLog2ZeroAlwaysThrows() {
    for (RoundingMode mode : ALL_ROUNDING_MODES) {
      try {

  }

  public void testIsPowerOfTwo() {
    for (BigInteger x : ALL_BIGINTEGER_CANDIDATES) {
      // Checks for a single bit set.
      boolean expected = x.signum() > 0 & x.and(x.subtract(ONE)).equals(ZERO);
      assertEquals(expected, BigIntegerMath.isPowerOfTwo(x));
    }
  }

  public void testLog2ZeroAlwaysThrows() {
    for (RoundingMode mode : ALL_ROUNDING_MODES) {
      try {

      return value.subtract(BigInteger.ONE);
    }

    @Override
    BigInteger offset(BigInteger origin, long distance) {
      checkNonnegative(distance, "distance");
      return origin.add(BigInteger.valueOf(distance));
    }

    @Override
    public long distance(BigInteger start, BigInteger end) {
      return end.subtract(start).max(MIN_LONG).min(MAX_LONG).longValue();
    }

      return value.subtract(BigInteger.ONE);
    }

    @Override
    BigInteger offset(BigInteger origin, long distance) {
      checkNonnegative(distance, "distance");
      return origin.add(BigInteger.valueOf(distance));
    }

    @Override
    public long distance(BigInteger start, BigInteger end) {
      return end.subtract(start).max(MIN_LONG).min(MAX_LONG).longValue();
    }

    requireLinks()[i] = value;
  }

  /*
   * We don't define getPredecessor+getSuccessor and setPredecessor+setSuccessor here because
   * they're defined above -- including logic to add and subtract 1 to map between the values stored
   * in the predecessor/successor arrays and the indexes in the elements array that they identify.
   */

    return requireNonNull(successor);
  }

  /*
   * We don't define getPredecessor+getSuccessor and setPredecessor+setSuccessor here because
   * they're defined above -- including logic to add and subtract 1 to map between the values stored
   * in the predecessor/successor arrays and the indexes in the elements array that they identify.
   */

    checkBigIntegerConversion(
        "::ffff:ffff:ffff:ffff", BigInteger.ONE.shiftLeft(64).subtract(BigInteger.ONE));
    checkBigIntegerConversion(
        "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
        BigInteger.ONE.shiftLeft(128).subtract(BigInteger.ONE));
  }

  public void testFromIpv4BigIntegerInputTooLarge() {
    IllegalArgumentException expected =
        assertThrows(

  }

  @AndroidIncompatible // slow
  public void testCheckedSubtract() {
    for (int a : ALL_INTEGER_CANDIDATES) {
      for (int b : ALL_INTEGER_CANDIDATES) {
        BigInteger expectedResult = valueOf(a).subtract(valueOf(b));
        boolean expectedSuccess = fitsInInt(expectedResult);
        try {
          assertEquals(a - b, IntMath.checkedSubtract(a, b));
          assertTrue(expectedSuccess);

    checkBigIntegerConversion(
        "::ffff:ffff:ffff:ffff", BigInteger.ONE.shiftLeft(64).subtract(BigInteger.ONE));
    checkBigIntegerConversion(
        "ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff",
        BigInteger.ONE.shiftLeft(128).subtract(BigInteger.ONE));
  }

  public void testFromIpv4BigIntegerInputTooLarge() {
    IllegalArgumentException expected =
        assertThrows(

    assertThat(UnsignedLongs.parseUnsignedLong("1234567890abcdef", 16))
        .isEqualTo(0x1234567890abcdefL);
  }

  public void testParseLongWithRadixLimits() {
    BigInteger max = BigInteger.ZERO.setBit(64).subtract(ONE);
    // loops through all legal radix values.
    for (int radix = Character.MIN_RADIX; radix <= Character.MAX_RADIX; radix++) {
      // tests can successfully parse a number string with this radix.