}
    }
  }

  @GwtIncompatible // TODO
  public void testSqrtHalfUp() {
    for (BigInteger x : POSITIVE_BIGINTEGER_CANDIDATES) {
      BigInteger result = BigIntegerMath.sqrt(x, HALF_UP);
      BigInteger plusHalfSquared = result.pow(2).add(result).shiftLeft(2).add(ONE);
      BigInteger x4 = x.shiftLeft(2);
      // sqrt(x) < result + 0.5, so 4 * x < (result + 0.5)^2 * 4

          .add(doubleConversionTest + i);
      BigInteger bigI = BigInteger.valueOf(i);
      testBigIntegersBuilder
          .add(bigI)
          .add(BigInteger.valueOf(Long.MAX_VALUE).add(bigI))
          .add(BigInteger.valueOf(Long.MIN_VALUE).add(bigI))
          .add(BigInteger.valueOf(Integer.MAX_VALUE).add(bigI))
          .add(BigInteger.valueOf(Integer.MIN_VALUE).add(bigI))
          .add(BigInteger.ONE.shiftLeft(63).add(bigI))

   */
  static final ImmutableSet<BigInteger> POSITIVE_BIGINTEGER_CANDIDATES;

  static final Iterable<BigInteger> NEGATIVE_BIGINTEGER_CANDIDATES;

  static final Iterable<BigInteger> NONZERO_BIGINTEGER_CANDIDATES;

  static final Iterable<BigInteger> ALL_BIGINTEGER_CANDIDATES;

  static {
    ImmutableSet.Builder<BigInteger> bigValues = ImmutableSet.builder();

        () -> MathPreconditions.checkPositive("BigInteger", BigInteger.ZERO));
  }

  public void testCheckPositive_positiveBigInteger() {
    MathPreconditions.checkPositive("BigInteger", BigInteger.ONE);
  }

  public void testCheckPositive_negativeBigInteger() {
    assertThrows(
        IllegalArgumentException.class,
        () -> MathPreconditions.checkPositive("BigInteger", BigInteger.ZERO.negate()));
  }

        () -> MathPreconditions.checkPositive("BigInteger", BigInteger.ZERO));
  }

  public void testCheckPositive_positiveBigInteger() {
    MathPreconditions.checkPositive("BigInteger", BigInteger.ONE);
  }

  public void testCheckPositive_negativeBigInteger() {
    assertThrows(
        IllegalArgumentException.class,
        () -> MathPreconditions.checkPositive("BigInteger", BigInteger.ZERO.negate()));
  }

   * Returns the {@code Inet4Address} corresponding to a given {@code BigInteger}.
   *
   * @param address BigInteger representing the IPv4 address
   * @return Inet4Address representation of the given BigInteger
   * @throws IllegalArgumentException if the BigInteger is not between 0 and 2^32-1
   * @since 28.2
   */
  public static Inet4Address fromIPv4BigInteger(BigInteger address) {

import static com.google.common.truth.Truth.assertThat;
import static org.junit.Assert.assertThrows;

import com.google.common.annotations.GwtIncompatible;
import com.google.errorprone.annotations.FormatMethod;
import java.math.BigInteger;
import junit.framework.TestCase;
import org.jspecify.annotations.NullUnmarked;

/**
 * Tests for {@link DoubleUtils}.
 *
 * @author Louis Wasserman
 */
@GwtIncompatible
@NullUnmarked

    long significand = doubleToRawLongBits(x) & SIGNIFICAND_MASK;
    return longBitsToDouble(significand | ONE_BITS);
  }

  static double bigToDouble(BigInteger x) {
    // This is an extremely fast implementation of BigInteger.doubleValue(). JDK patch pending.
    BigInteger absX = x.abs();
    int exponent = absX.bitLength() - 1;
    // exponent == floor(log2(abs(x)))
    if (exponent < Long.SIZE - 1) {
      return x.longValue();

    checkBigIntegerConversion(
        "255.255.255.254", BigInteger.valueOf(Integer.MAX_VALUE).multiply(BigInteger.valueOf(2)));
    checkBigIntegerConversion(
        "255.255.255.255", BigInteger.ONE.shiftLeft(32).subtract(BigInteger.ONE));
  }

  public void testFromIpv6BigIntegerValid() {
    checkBigIntegerConversion("::", BigInteger.ZERO);
    checkBigIntegerConversion("::1", BigInteger.ONE);

    return source.readByte().toInt() != 0
  }

  fun readBigInteger(): BigInteger {
    if (bytesLeft == 0L) throw ProtocolException("unexpected length: $bytesLeft at $this")
    val byteArray = source.readByteArray(bytesLeft)
    return BigInteger(byteArray)
  }

  fun readLong(): Long {