assertEquals("010203", StringUtil.toHex(new byte[] { 1, 2, 3 }));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testToHex2() throws Exception {
        assertEquals("0001", StringUtil.toHex(1));
    }

    /**
     * @throws Exception
     */
    @Test
    public void testAppendHex() throws Exception {
        final StringBuilder buf = new StringBuilder();

  /**
   * Maximum allowed false positive probability of detecting a hash flooding attack given random
   * input.
   */
  @VisibleForTesting static final double HASH_FLOODING_FPP = 0.001;

  /**
   * Maximum allowed length of a hash table bucket before falling back to a j.u.HashMap based
   * implementation. Experimentally determined.
   */
  static final int MAX_HASH_BUCKET_LENGTH = 8;

    for (int exp : asList(-1022, -50, -1, 0, 1, 2, 3, 4, 100, 1022, 1023)) {
      for (RoundingMode mode : asList(HALF_EVEN, HALF_UP, HALF_DOWN)) {
        double x = Math.scalb(Math.sqrt(2) + 0.001, exp);
        double y = Math.scalb(Math.sqrt(2) - 0.001, exp);
        if (exp < 0) {
          assertEquals(exp + 1, DoubleMath.log2(x, mode));
          assertEquals(exp, DoubleMath.log2(y, mode));
        } else {

 *   <dt>From the IPv6 reserved documentation prefix ({@code 2001:db8::/32}), {@code "2001:db8::1"}.
 *   <dd>{@code 20 01 0d b8 00 00 00 00 00 00 00 00 00 00 00 01}
 *   <dt>An IPv6 "IPv4 compatible" (or "compat") address, {@code "::192.168.0.1"}.
 *   <dd>{@code 00 00 00 00 00 00 00 00 00 00 00 00 c0 a8 00 01}
 *   <dt>An IPv6 "IPv4 mapped" address, {@code "::ffff:192.168.0.1"}.

  }

  public void testIncrementIPv6() throws UnknownHostException {
    InetAddress addressV6_66_0 = InetAddress.getByName("2001:db8::6600");
    InetAddress addressV6_66_ff = InetAddress.getByName("2001:db8::66ff");
    InetAddress addressV6_67_0 = InetAddress.getByName("2001:db8::6700");

    InetAddress address = addressV6_66_0;
    for (int i = 0; i < 255; i++) {
      address = InetAddresses.increment(address);

  }

  /**
   * Maximum allowed false positive probability of detecting a hash flooding attack given random
   * input.
   */
  @VisibleForTesting(
      )
  static final double HASH_FLOODING_FPP = 0.001;

  /**
   * Maximum allowed length of a hash table bucket before falling back to a j.u.LinkedHashSet based
   * implementation. Experimentally determined.
   */
  private static final int MAX_HASH_BUCKET_LENGTH = 9;

    for (int exp : asList(-1022, -50, -1, 0, 1, 2, 3, 4, 100, 1022, 1023)) {
      for (RoundingMode mode : asList(HALF_EVEN, HALF_UP, HALF_DOWN)) {
        double x = Math.scalb(Math.sqrt(2) + 0.001, exp);
        double y = Math.scalb(Math.sqrt(2) - 0.001, exp);
        if (exp < 0) {
          assertEquals(exp + 1, DoubleMath.log2(x, mode));
          assertEquals(exp, DoubleMath.log2(y, mode));
        } else {

  }

  /** Tests that we always get a non-negative optimal size. */
  public void testOptimalSize() {
    for (int n = 1; n < 1000; n++) {
      for (double fpp = Double.MIN_VALUE; fpp < 1.0; fpp += 0.001) {
        assertTrue(BloomFilter.optimalNumOfBits(n, fpp) >= 0);
      }
    }

    // some random values
    Random random = new Random(0);
    for (int repeats = 0; repeats < 10000; repeats++) {

	LTDBR	F3, F4                 // b3120043
	TCEB	F5, $8                 // ed5000080010
	TCDB	F15, $4095             // edf00fff0011

	UNDEF                          // 00000000
	BRRK			       // 0001
	NOPH                           // 0700

	SYNC                           // 07e0

	KM	R2, R4                 // b92e0024
	KMC	R2, R6                 // b92f0026
	KLMD	R2, R8                 // b93f0028

 *   <dt>From the IPv6 reserved documentation prefix ({@code 2001:db8::/32}), {@code "2001:db8::1"}.
 *   <dd>{@code 20 01 0d b8 00 00 00 00 00 00 00 00 00 00 00 01}
 *   <dt>An IPv6 "IPv4 compatible" (or "compat") address, {@code "::192.168.0.1"}.
 *   <dd>{@code 00 00 00 00 00 00 00 00 00 00 00 00 c0 a8 00 01}
 *   <dt>An IPv6 "IPv4 mapped" address, {@code "::ffff:192.168.0.1"}.