UrlQueueImpl<Long> queue = new UrlQueueImpl<>();
        assertNotNull(queue);
        assertNull(queue.getId());
        assertNull(queue.getSessionId());
        assertNull(queue.getMethod());
        assertNull(queue.getUrl());
        assertNull(queue.getMetaData());
        assertNull(queue.getEncoding());
        assertNull(queue.getParentUrl());
        assertNull(queue.getDepth());

import java.util.concurrent.atomic.AtomicReference;
import org.jspecify.annotations.Nullable;

/**
 * Serializes execution of tasks, somewhat like an "asynchronous {@code synchronized} block." Each
 * {@linkplain #submit enqueued} callable will not be submitted to its associated executor until the
 * previous callable has returned -- and, if the previous callable was an {@link AsyncCallable}, not

Shinsuke Sugaya <******@****.***> 1730954650 +0900

  public void testOffer_supportedNotPresent() {
    assertTrue("offer(notPresent) should return true", getQueue().offer(e3()));
    expectAdded(e3());
  }

  @CollectionFeature.Require({SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  public void testOffer_nullSupported() {
    assertTrue("offer(null) should return true", getQueue().offer(null));
    expectAdded((E) null);
  }

  private val taskRunner = TaskRunner(backend)
  private val queue = taskRunner.newQueue()

  @AfterEach fun tearDown() {
    backend.shutdown()
  }

  @Test fun test() {
    val t1 = System.nanoTime() / 1e6

    val delays = mutableListOf(TimeUnit.MILLISECONDS.toNanos(1000), -1L)
    queue.schedule("task", TimeUnit.MILLISECONDS.toNanos(750)) {
      log.put("runOnce delays.size=${delays.size}")

  @CollectionSize.Require(ZERO)
  public void testElement_empty() {
    assertThrows(NoSuchElementException.class, () -> getQueue().element());
    expectUnchanged();
  }

  @CollectionSize.Require(ONE)
  public void testElement_size1() {
    assertEquals("size1Queue.element() should return first element", e0(), getQueue().element());
    expectUnchanged();
  }

  @CollectionFeature.Require(KNOWN_ORDER)

  @CollectionSize.Require(ZERO)
  public void testPeek_empty() {
    assertNull("emptyQueue.peek() should return null", getQueue().peek());
    expectUnchanged();
  }

  @CollectionSize.Require(ONE)
  public void testPeek_size1() {
    assertEquals("size1Queue.peek() should return first element", e0(), getQueue().peek());
    expectUnchanged();
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  @CollectionSize.Require(SEVERAL)

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class AbstractQueueTester<E> extends AbstractCollectionTester<E> {
  protected final Queue<E> getQueue() {
    return (Queue<E>) collection;
  }

  public void testOffer_supportedNotPresent() {
    assertTrue("offer(notPresent) should return true", getQueue().offer(e3()));
    expectAdded(e3());
  }

  @CollectionFeature.Require({SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  public void testOffer_nullSupported() {
    assertTrue("offer(null) should return true", getQueue().offer(null));
    expectAdded((E) null);
  }

  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());
  }