assertThat(ArbitraryInstances.get(Ticker.class)).isNotNull();
    assertFreshInstanceReturned(Random.class);
    assertEquals(
        ArbitraryInstances.get(Random.class).nextInt(),
        ArbitraryInstances.get(Random.class).nextInt());
  }

  public void testGet_concurrent() {
    assertTrue(ArbitraryInstances.get(BlockingDeque.class).isEmpty());
    assertTrue(ArbitraryInstances.get(BlockingQueue.class).isEmpty());

      new ThreadLocal<Random>() {
        @Override
        protected Random initialValue() {
          return new Random();
        }
      };

  private static final int GOLDEN_PRESENT_KEY = random.get().nextInt();

  @AndroidIncompatible // OutOfMemoryError
  public void testLargeBloomFilterDoesntOverflow() {
    long numBits = Integer.MAX_VALUE;
    numBits++;

    LockFreeBitArray bitArray = new LockFreeBitArray(numBits);

    assertThat(ArbitraryInstances.get(Ticker.class)).isNotNull();
    assertFreshInstanceReturned(Random.class);
    assertEquals(
        ArbitraryInstances.get(Random.class).nextInt(),
        ArbitraryInstances.get(Random.class).nextInt());
  }

  public void testGet_concurrent() {
    assertTrue(ArbitraryInstances.get(BlockingDeque.class).isEmpty());
    assertTrue(ArbitraryInstances.get(BlockingQueue.class).isEmpty());

    for (int i = 0; i < heapSize; i++) {
      mmHeap.add(random.nextInt());
    }
    for (int i = 0; i < numberOfModifications; i++) {
      mmHeap.removeAtForTesting(random.nextInt(mmHeap.size()));
      assertIntactUsingSeed(seed, mmHeap);
      mmHeap.add(random.nextInt());
      assertIntactUsingSeed(seed, mmHeap);
    }
  }

  public void testRemoveAt_exhaustive() {

    for (int i = 0; i < heapSize; i++) {
      mmHeap.add(random.nextInt());
    }
    for (int i = 0; i < numberOfModifications; i++) {
      mmHeap.removeAtForTesting(random.nextInt(mmHeap.size()));
      assertIntactUsingSeed(seed, mmHeap);
      mmHeap.add(random.nextInt());
      assertIntactUsingSeed(seed, mmHeap);
    }
  }

  public void testRemoveAt_exhaustive() {

    for (int trial = 0; trial < 100; trial++) {
      byte[] left = new byte[1 + rnd.nextInt(32)];
      rnd.nextBytes(left);
      byte[] right = left.clone();
      assertThat(comparator1.compare(left, right)).isEqualTo(0);
      assertThat(comparator2.compare(left, right)).isEqualTo(0);
      int i = rnd.nextInt(left.length);
      left[i] ^= (byte) (1 + rnd.nextInt(255));
      assertThat(signum(comparator1.compare(left, right)))

  public void testEncodedStringInputs() {
    Random rng = new Random(0);
    for (int z = 0; z < 100; z++) {
      int[] codePoints = new int[rng.nextInt(8)];
      for (int i = 0; i < codePoints.length; i++) {
        do {
          codePoints[i] = rng.nextInt(0x800);
        } while (!Character.isValidCodePoint(codePoints[i])
            || (codePoints[i] >= Character.MIN_SURROGATE

      // if expected.length == 0, off has to be 0 but length doesn't matter--result will be empty
      int off = expected.length == 0 ? 0 : random.nextInt(expected.length);
      int len = expected.length == 0 ? 4 : random.nextInt(expected.length - off);

      ByteSourceFactory sliced = SourceSinkFactories.asSlicedByteSourceFactory(factory, off, len);

    for (int trial = 0; trial < 100; trial++) {
      byte[] left = new byte[1 + rnd.nextInt(32)];
      rnd.nextBytes(left);
      byte[] right = left.clone();
      assertThat(comparator1.compare(left, right)).isEqualTo(0);
      assertThat(comparator2.compare(left, right)).isEqualTo(0);
      int i = rnd.nextInt(left.length);
      left[i] ^= (byte) (1 + rnd.nextInt(255));
      assertThat(signum(comparator1.compare(left, right)))

  public void testEncodedStringInputs() {
    Random rng = new Random(0);
    for (int z = 0; z < 100; z++) {
      int[] codePoints = new int[rng.nextInt(8)];
      for (int i = 0; i < codePoints.length; i++) {
        do {
          codePoints[i] = rng.nextInt(0x800);
        } while (!Character.isValidCodePoint(codePoints[i])
            || (codePoints[i] >= Character.MIN_SURROGATE