}

  /** Returns a hash function implementing the SHA-256 algorithm (256 hash bits). */
  public static HashFunction sha256() {
    return Sha256Holder.SHA_256;
  }

  private static class Sha256Holder {
    static final HashFunction SHA_256 =
        new MessageDigestHashFunction("SHA-256", "Hashing.sha256()");
  }

  /**

  public void testNewArrayListWithCapacity() {
    ArrayList<Integer> list = Lists.newArrayListWithCapacity(0);
    assertEquals(Collections.emptyList(), list);

    ArrayList<Integer> bigger = Lists.newArrayListWithCapacity(256);
    assertEquals(Collections.emptyList(), bigger);
  }

  public void testNewArrayListWithCapacity_negative() {
    try {
      Lists.newArrayListWithCapacity(-1);
      fail();

      }
    }
  }

  public void testCorrectOrdering_mediumHeapsPollFirst() {
    for (int attempts = 0; attempts < reduceIterationsIfGwt(5000); attempts++) {
      int size = new Random().nextInt(256) + 16;
      ArrayList<Integer> elements = createOrderedList(size);
      List<Integer> expected = ImmutableList.copyOf(elements);
      MinMaxPriorityQueue<Integer> q = MinMaxPriorityQueue.create();

  public void testNewArrayListWithCapacity() {
    ArrayList<Integer> list = Lists.newArrayListWithCapacity(0);
    assertEquals(Collections.emptyList(), list);

    ArrayList<Integer> bigger = Lists.newArrayListWithCapacity(256);
    assertEquals(Collections.emptyList(), bigger);
  }

  public void testNewArrayListWithCapacity_negative() {
    try {
      Lists.newArrayListWithCapacity(-1);
      fail();

    }

    private Base16Encoding(Alphabet alphabet) {
      super(alphabet, null);
      checkArgument(alphabet.chars.length == 16);
      for (int i = 0; i < 256; ++i) {
        encoding[i] = alphabet.encode(i >>> 4);
        encoding[i | 0x100] = alphabet.encode(i & 0xF);
      }
    }

    @Override

      }
    }
  }

  public void testCorrectOrdering_mediumHeapsPollFirst() {
    for (int attempts = 0; attempts < reduceIterationsIfGwt(5000); attempts++) {
      int size = new Random().nextInt(256) + 16;
      ArrayList<Integer> elements = createOrderedList(size);
      List<Integer> expected = ImmutableList.copyOf(elements);
      MinMaxPriorityQueue<Integer> q = MinMaxPriorityQueue.create();