Spliterator.SIZED | Spliterator.DISTINCT | Spliterator.NONNULL,
                    7))
        .expect('a', 'b', 'c', 'd', 'e', 'f', 'g');
  }

  public void testFlatMap_nullStream() {
    SpliteratorTester.of(
            () ->
                CollectSpliterators.flatMap(
                    Arrays.spliterator(new String[] {"abc", "", "de", "f", "g", ""}),

    initCollectionWithNullElement();
    assertFalse(collection.spliterator().hasCharacteristics(Spliterator.NONNULL));
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testSpliteratorNotImmutable_collectionAllowsAdd() {
    // If add is supported, verify that IMMUTABLE is not reported.
    assertFalse(collection.spliterator().hasCharacteristics(Spliterator.IMMUTABLE));
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)

  }

  @Override
  @GwtIncompatible // Spliterator
  Spliterator<Entry<K, V>> entrySpliterator() {
    return CollectSpliterators.map(
        delegate.entrySet().spliterator(),
        Spliterator.DISTINCT | Spliterator.ORDERED | Spliterator.IMMUTABLE | Spliterator.NONNULL,
        Maps::unmodifiableEntry);
  }

  @Override

    int expectedCharacteristics =
        Spliterator.DISTINCT | Spliterator.ORDERED | Spliterator.NONNULL | Spliterator.IMMUTABLE;
    Spliterator<Entry<AnEnum, String>> spliterator =
        immutableEnumMap(ImmutableMap.of(AnEnum.A, "a", AnEnum.B, "b")).entrySet().spliterator();
    Truth.assertWithMessage(spliterator.getClass().toString())
        .that(spliterator.characteristics() & expectedCharacteristics)

      }

      @Override
      @GwtIncompatible // Spliterator
      public Spliterator<Entry<Class<? extends @NonNull B>, B>> spliterator() {
        return CollectSpliterators.map(
            delegate().spliterator(),
            Spliterator.DISTINCT | Spliterator.NONNULL,
            MutableClassToInstanceMap::checkedEntry);
      }

      @Override

    // The fake cast to E is safe because the creation methods only allow E's
    return (UnmodifiableListIterator<E>) Iterators.forArrayWithPosition(array, index);
  }

  @Override
  public Spliterator<E> spliterator() {
    return Spliterators.spliterator(array, SPLITERATOR_CHARACTERISTICS);
  }

  // TODO(lowasser): benchmark optimizations for equals() and see if they're worthwhile

  // redeclare to help optimizers with b/310253115

   *
   * - For stream() and spliterator(), we have to forward to the delegate ourselves because
   *   ForwardingSet does not forward `default` methods, as discussed in its Javadoc.
   */

  @Override
  public Stream<E> stream() {
    return delegate.stream();
  }

  @Override
  public Spliterator<E> spliterator() {
    return delegate.spliterator();
  }

  @Override

@GwtCompatible
abstract class ImmutableMapEntrySet<K, V> extends ImmutableSet.CachingAsList<Entry<K, V>> {
  private static final int SPLITERATOR_CHARACTERISTICS =
      Spliterator.ORDERED | Spliterator.DISTINCT | Spliterator.NONNULL | Spliterator.IMMUTABLE;

  static final class RegularEntrySet<K, V> extends ImmutableMapEntrySet<K, V> {
    private final transient ImmutableMap<K, V> map;
    private final transient ImmutableList<Entry<K, V>> entries;

    return element;
  }

  @Override
  public UnmodifiableIterator<E> iterator() {
    return singletonIterator(element);
  }

  @Override
  public Spliterator<E> spliterator() {
    return singleton(element).spliterator();
  }

  @Override
  public int size() {
    return 1;
  }

  @Override
  public ImmutableList<E> subList(int fromIndex, int toIndex) {

  }

  @Override
  Set<Entry<K, V>> createEntrySet() {
    @WeakOuter
    final class EntrySetImpl extends EntrySetView {
      @Override
      public Spliterator<Entry<K, V>> spliterator() {
        return Spliterators.spliterator(this, Spliterator.ORDERED | Spliterator.DISTINCT);
      }
    }
    return new EntrySetImpl();
  }

  @Override
  Set<K> createKeySet() {
    @WeakOuter