Random rand = new Random(1);
    for (int bits = 10; bits < 63; bits++) {
      for (int i = 0; i < 100; i++) {
        long p = BigInteger.probablePrime(bits, rand).longValue();
        assertTrue(LongMath.isPrime(p));
      }
    }
  }

  @GwtIncompatible // isPrime is GWT-incompatible
  public void testIsPrimeOnRandomComposites() {
    Random rand = new Random(1);

 *
 * <p>See the Guava User Guide article on <a
 * href="https://github.com/google/guava/wiki/PrimitivesExplained#unsigned-support">unsigned
 * primitive utilities</a>.
 *
 * @author Louis Wasserman
 * @author Brian Milch
 * @author Colin Evans
 * @since 10.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public final class UnsignedLongs {
  private UnsignedLongs() {}