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)

    checkNotNull(stream);
    checkNotNull(function);
    boolean isParallel = stream.isParallel();
    Spliterator<T> fromSpliterator = stream.spliterator();

    if (!fromSpliterator.hasCharacteristics(Spliterator.SUBSIZED)) {
      Iterator<T> fromIterator = Spliterators.iterator(fromSpliterator);
      return StreamSupport.stream(
              new AbstractSpliterator<R>(