public void testPoll_empty() {
    assertNull("emptyQueue.poll() should return null", getQueue().poll());
    expectUnchanged();
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ONE)
  public void testPoll_size1() {
    assertEquals("size1Queue.poll() should return first element", e0(), getQueue().poll());
    expectMissing(e0());
  }

  public void testPoll_empty() {
    assertNull("emptyQueue.poll() should return null", getQueue().poll());
    expectUnchanged();
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(ONE)
  public void testPoll_size1() {
    assertEquals("size1Queue.poll() should return first element", e0(), getQueue().poll());
    expectMissing(e0());
  }

    while (added < numElements) {
      // we could rely solely on #poll, but #drainTo might be more efficient when there are multiple
      // elements already available (e.g. LinkedBlockingQueue#drainTo locks only once)
      added += q.drainTo(buffer, numElements - added);
      if (added < numElements) { // not enough elements immediately available; will have to poll
        E e = q.poll(deadline - System.nanoTime(), TimeUnit.NANOSECONDS);

    assertEquals(1, (int) mmHeap.peek());
    assertEquals(1, (int) mmHeap.poll());
    assertEquals(3, (int) mmHeap.peekLast());
    assertEquals(2, (int) mmHeap.peek());
    assertEquals(2, (int) mmHeap.poll());
    assertEquals(3, (int) mmHeap.peekLast());
    assertEquals(3, (int) mmHeap.peek());
    assertEquals(3, (int) mmHeap.poll());
    assertNull(mmHeap.peekLast());
    assertNull(mmHeap.peek());

        assertFalse(map.containsValue(valueOne));
        assertNull(map.get(keyOne));
        assertEquals(1, map.size());
        assertNull(segment.getKeyReferenceQueueForTesting().poll());
      }
    }
  }

  public void testDrainValueReferenceQueueOnWrite() {
    for (MapMaker maker : allWeakValueStrengthMakers()) {

        assertFalse(map.containsValue(valueOne));
        assertNull(map.get(keyOne));
        assertEquals(1, map.size());
        assertNull(segment.getKeyReferenceQueueForTesting().poll());
      }
    }
  }

  public void testDrainValueReferenceQueueOnWrite() {
    for (MapMaker maker : allWeakValueStrengthMakers()) {

 *     .maximumSize(1000)
 *     .create();
 * }</pre>
 *
 * <p>As a {@link Queue} it functions exactly as a {@link PriorityQueue}: its head element -- the
 * implicit target of the methods {@link #peek()}, {@link #poll()} and {@link #remove()} -- is
 * defined as the <i>least</i> element in the queue according to the queue's comparator. But unlike
 * a regular priority queue, the methods {@link #peekLast}, {@link #pollLast} and {@link

                // from execute().
                workerRunCount++;
                workerRunningState = RUNNING;
                hasSetRunning = true;
              }
            }
            task = queue.poll();
            if (task == null) {
              workerRunningState = IDLE;
              return;
            }
          }

  /**
   * Starts the Finalizer thread. FinalizableReferenceQueue calls this method reflectively.
   *
   * @param finalizableReferenceClass FinalizableReference.class.
   * @param queue a reference queue that the thread will poll.
   * @param frqReference a phantom reference to the FinalizableReferenceQueue, which will be queued
   *     either when the FinalizableReferenceQueue is no longer referenced anywhere, or when its
   *     close() method is called.

      // If even the first one wasn't there, clean up so that the next test doesn't see an element.
      producerThread.cancel(true);
      producer.doneProducing.await();
      if (drained == 0) {
        q.poll(); // not necessarily there if producer was interrupted
      }
    }
  }

  public void testZeroElements() throws Exception {
    for (BlockingQueue<Object> q : blockingQueues()) {
      testZeroElements(q);