// also mean that the iterator returns the head element first, which those
  // don't.

  public Test testsForPriorityBlockingQueue() {
    return QueueTestSuiteBuilder.using(
            new TestStringQueueGenerator() {
              @Override
              public Queue<String> create(String[] elements) {
                return new PriorityBlockingQueue<>(MinimalCollection.of(elements));
              }
            })

    collection = getSubjectGenerator().create(arrayAndDuplicate.elements);
    E duplicate = arrayAndDuplicate.duplicate;

    int firstIndex = getList().indexOf(duplicate);
    int initialSize = getList().size();
    assertTrue("remove(present) should return true", getList().remove(duplicate));
    assertTrue(
        "After remove(duplicate), a list should still contain the duplicate element",
        getList().contains(duplicate));
    assertFalse(

    collection = getSubjectGenerator().create(arrayAndDuplicate.elements);
    E duplicate = arrayAndDuplicate.duplicate;

    int firstIndex = getList().indexOf(duplicate);
    int initialSize = getList().size();
    assertTrue("remove(present) should return true", getList().remove(duplicate));
    assertTrue(
        "After remove(duplicate), a list should still contain the duplicate element",
        getList().contains(duplicate));
    assertFalse(

    }

    @Override
    public @Nullable E peek() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.peek();
    }

    @Override
    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override
    public Iterator<E> iterator() {
      // We explicitly don't lock for iterator()
      assertFalse(Thread.holdsLock(mutex));

  public SampleElements<Entry<K, V>> samples() {
    return SampleElements.mapEntries(keys, values);
  }

  @Override
  public Set<Entry<K, V>> create(Object... elements) {
    Entry<K, V>[] entries = createArray(elements.length);
    arraycopy(elements, 0, entries, 0, elements.length);
    return createFromEntries(entries);
  }

  public abstract Set<Entry<K, V>> createFromEntries(Entry<K, V>[] entries);

  @Override

  /**
   * Returns the next element in the iteration, without advancing the iteration.
   *
   * <p>Calls to {@code peek()} should not change the state of the iteration, except that it
   * <i>may</i> prevent removal of the most recent element via {@link #remove()}.
   *
   * @throws NoSuchElementException if the iteration has no more elements according to {@link
   *     #hasNext()}
   */
  @ParametricNullness

    }

    @Override
    public @Nullable E peek() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.peek();
    }

    @Override
    public E element() {
      assertTrue(Thread.holdsLock(mutex));
      return delegate.element();
    }

    @Override
    public Iterator<E> iterator() {
      // We explicitly don't lock for iterator()
      assertFalse(Thread.holdsLock(mutex));

      return samples;
    }

    @Override
    public Set<K> create(Object... elements) {
      @SuppressWarnings("unchecked")
      K[] keysArray = (K[]) elements;

      // Start with a suitably shaped collection of entries
      Collection<Entry<K, V>> originalEntries = mapGenerator.getSampleElements(elements.length);

      // Create a copy of that, with the desired value for each key

    protected List<Byte> create(Byte[] elements) {
      return asList(elements);
    }
  }

  public static final class BytesAsListHeadSubListGenerator extends TestByteListGenerator {
    @Override
    protected List<Byte> create(Byte[] elements) {
      Byte[] suffix = {Byte.MIN_VALUE, Byte.MAX_VALUE};
      Byte[] all = concat(elements, suffix);
      return asList(all).subList(0, elements.length);
    }
  }

    protected List<Long> create(Long[] elements) {
      return asList(elements);
    }
  }

  public static final class LongsAsListHeadSubListGenerator extends TestLongListGenerator {
    @Override
    protected List<Long> create(Long[] elements) {
      Long[] suffix = {Long.MIN_VALUE, Long.MAX_VALUE};
      Long[] all = concat(elements, suffix);
      return asList(all).subList(0, elements.length);
    }
  }