}

  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) {

    }

    @Override
    BigDecimal toX(double d, RoundingMode mode) {
      return new BigDecimal(d);
    }

    @Override
    BigDecimal minus(BigDecimal a, BigDecimal b) {
      return a.subtract(b);
    }
  }

    }

    @Override
    BigDecimal toX(double d, RoundingMode mode) {
      return new BigDecimal(d);
    }

    @Override
    BigDecimal minus(BigDecimal a, BigDecimal b) {
      return a.subtract(b);
    }
  }

  }

  @AndroidIncompatible // slow
  public void testLessThanBranchFree() {
    for (long x : ALL_LONG_CANDIDATES) {
      for (long y : ALL_LONG_CANDIDATES) {
        BigInteger difference = BigInteger.valueOf(x).subtract(BigInteger.valueOf(y));
        if (fitsInLong(difference)) {
          int expected = (x < y) ? 1 : 0;
          int actual = LongMath.lessThanBranchFree(x, y);
          assertEquals(expected, actual);
        }

            513,
            Double.MAX_EXPONENT - 1,
            Double.MAX_EXPONENT,
            Double.MAX_EXPONENT + 1)) {
      BigInteger x = ONE.shiftLeft(exponent);
      bigValues.add(x, x.add(ONE), x.subtract(ONE));
    }
    bigValues.add(new BigInteger("218838949120258359057546633")); // sqrt(2^175) rounded up and
    // down
    bigValues.add(new BigInteger("218838949120258359057546634"));

        UnsignedInteger aUnsigned = UnsignedInteger.fromIntBits(a);
        UnsignedInteger bUnsigned = UnsignedInteger.fromIntBits(b);
        int expected =
            force32(aUnsigned.bigIntegerValue().subtract(bUnsigned.bigIntegerValue()).intValue());
        UnsignedInteger unsignedSub = aUnsigned.minus(bUnsigned);
        assertThat(unsignedSub.intValue()).isEqualTo(expected);
      }
    }
  }

            // in DST
            if (cfg.getLocalTimezone().inDaylightTime(new Date(t))) {
                // t also in DST so no correction
            } else {
                // t not in DST so subtract 1 hour
                t -= 3600000;
            }
        } else // not in DST
        if (cfg.getLocalTimezone().inDaylightTime(new Date(t))) {
            // t is in DST so add 1 hour
            t += 3600000;

  }

  @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);

    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.
   */

    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 r = Character.MIN_RADIX; r <= Character.MAX_RADIX; r++) {
      int radix = r;
      // tests can successfully parse a number string with this radix.