* @return the contents of the container under test, for use by {@link #expectContents(Object[])
   *     expectContents(E...)} and its friends.
   */
  protected abstract Collection<E> actualContents();

  /**
   * Replaces the existing container under test with a new container created by the subject
   * generator.
   *
   * @see #resetContainer(Object) resetContainer(C)
   * @return the new container instance.
   */

-   [guava-discuss: For open-ended questions and discussion](https://groups.google.com/group/guava-discuss)

## IMPORTANT WARNINGS

1. APIs marked with the `@Beta` annotation at the class or method level
are subject to change. They can be modified in any way, or even
removed, at any time. If your code is a library itself (i.e. it is
used on the CLASSPATH of users outside your own control), you should

    initCollectionWithNullElement();
    expectReturnsTrue(disjoint);
    expectContents();
  }

  // retainAll(null)

  /*
   * AbstractCollection fails the retainAll(null) test when the subject
   * collection is empty, but we'd still like to test retainAll(null) when we
   * can. We split the test into empty and non-empty cases. This allows us to
   * suppress only the former.
   */

/**
 * To be implemented by test generators that can produce test subjects without requiring any
 * parameters.
 *
 * @param <T> the type created by this generator.
 * @author George van den Driessche
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface TestSubjectGenerator<T extends @Nullable Object> {
  T createTestSubject();

      MapMakerInternalMap<Object, Object, ?, ?> map = makeMap(maker);
      Segment<Object, Object, ?, ?> segment = map.segments[0];

      Object keyOne = new Object();
      Object valueOne = new Object();
      int hashOne = map.hash(keyOne);
      InternalEntry<Object, Object, ?> entryOne = segment.newEntryForTesting(keyOne, hashOne, null);
      WeakValueReference<Object, Object, ?> valueRefOne =

      MapMakerInternalMap<Object, Object, ?, ?> map = makeMap(maker);
      Segment<Object, Object, ?, ?> segment = map.segments[0];

      Object keyOne = new Object();
      Object valueOne = new Object();
      int hashOne = map.hash(keyOne);
      InternalEntry<Object, Object, ?> entryOne = segment.newEntryForTesting(keyOne, hashOne, null);
      WeakValueReference<Object, Object, ?> valueRefOne =

    final Object one = new Object();
    final Object two = new Object();
    CacheLoader<Object, Object> loader =
        new CacheLoader<Object, Object>() {
          @Override
          public Object load(Object key) {
            return one;
          }

          @Override
          public ListenableFuture<Object> reload(Object key, Object oldValue) {

      @Override
      public Map<Object, Object> create(List<?> keys) {
        ImmutableMap.Builder<Object, Object> builder = ImmutableMap.builder();
        for (Object k : keys) {
          builder.put(k, "dummy value");
        }
        return builder.buildOrThrow();
      }
    },
    BUILDER_PUT_ENTRIES_ONE_BY_ONE {
      @Override
      public Map<Object, Object> create(List<?> keys) {

    Object computed = new Object();
    LoadingCache<Object, Object> cache =
        CacheBuilder.newBuilder()
            .expireAfterWrite(0, SECONDS)
            .removalListener(listener)
            .build(constantLoader(computed));

    Object key = new Object();
    assertSame(computed, cache.getUnchecked(key));
    RemovalNotification<Object, Object> notification = listener.remove();
    assertSame(key, notification.getKey());

    final List<Object> annotatedIn1And2AndClassEvents = Lists.newArrayList();
    final List<Object> declaredIn1AnnotatedIn2Events = Lists.newArrayList();
    final List<Object> declaredIn1AnnotatedInClassEvents = Lists.newArrayList();
    final List<Object> declaredIn2AnnotatedInClassEvents = Lists.newArrayList();
    final List<Object> annotatedIn2Events = Lists.newArrayList();