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);
  }

    for (int i = 0; i < 10; i++) {
      top.offer(i);
    }
    assertThat(top.topK()).isEmpty();
  }

  public void testNoElementsOffered() {
    TopKSelector<Integer> top = TopKSelector.least(10);
    assertThat(top.topK()).isEmpty();
  }

  public void testOfferedFewerThanK() {
    TopKSelector<Integer> top = TopKSelector.least(10);
    top.offer(3);
    top.offer(5);
    top.offer(2);

    for (int i = 0; i < 10; i++) {
      top.offer(i);
    }
    assertThat(top.topK()).isEmpty();
  }

  public void testNoElementsOffered() {
    TopKSelector<Integer> top = TopKSelector.least(10);
    assertThat(top.topK()).isEmpty();
  }

  public void testOfferedFewerThanK() {
    TopKSelector<Integer> top = TopKSelector.least(10);
    top.offer(3);
    top.offer(5);
    top.offer(2);

 * tailored to that use case.
 *
 * <p>This uses the same efficient implementation as {@link Ordering#leastOf(Iterable, int)},
 * offering expected O(n + k log k) performance (worst case O(n log k)) for n calls to {@link
 * #offer} and a call to {@link #topK}, with O(k) memory. In comparison, quickselect has the same
 * asymptotics but requires O(n) memory, and a {@code PriorityQueue} implementation takes O(n log

 *
 * <p>The classes in this package include:
 *
 * <h2>Immutable collections</h2>
 *
 * These are collections whose contents will never change. They also offer a few additional
 * guarantees (see {@link ImmutableCollection} for details). Implementations are available for both
 * the JDK collection types and the Guava collection types (listed below).
 *
 * <h2>Collection types</h2>
 *

   */
  @CanIgnoreReturnValue
  @Override
  public boolean add(E element) {
    offer(element);
    return true;
  }

  @CanIgnoreReturnValue
  @Override
  public boolean addAll(Collection<? extends E> newElements) {
    boolean modified = false;
    for (E element : newElements) {
      offer(element);
      modified = true;
    }
    return modified;
  }

  /**

      int k, Comparator<? super T> comparator) {
    checkNonnegative(k, "k");
    checkNotNull(comparator);
    return Collector.of(
        () -> TopKSelector.<T>least(k, comparator),
        TopKSelector::offer,
        TopKSelector::combine,
        TopKSelector::topK,
        Collector.Characteristics.UNORDERED);
  }

  /**

    SortedMap<Integer, AtomicInteger> replica = Maps.newTreeMap();
    assertTrue("Empty heap should be OK", mmHeap.isIntact());
    for (int i = 0; i < heapSize; i++) {
      int randomInt = random.nextInt();
      mmHeap.offer(randomInt);
      insertIntoReplica(replica, randomInt);
    }
    assertIntact(mmHeap);
    assertEquals(heapSize, mmHeap.size());
    int currentHeapSize = heapSize;

     * on what they know about the particular Joiner instances the calls are performed on.
     *
     * (In addition to useForNull, we also offer skipNulls. It, too, tolerates null inputs, but its
     * tolerance is implemented differently: Its implementation avoids calling this toString(Object)
     * method in the first place.)
     */
    requireNonNull(part);

   * key, the choice of {@link KeyAbsentBehavior} decides which index is returned.
   *
   * <p>This method runs in log(n) time on random-access lists, which offer near-constant-time
   * access to each list element.
   *
   * @param list the list to be searched.
   * @param key the value to be searched for.
   * @param comparator the comparator by which the list is ordered.