@SuppressWarnings("JUnit4ClassUsedInJUnit3")
@NullMarked
public class CollectionIteratorTester<E extends @Nullable Object>
    extends AbstractCollectionTester<E> {
  public void testIterator() {
    List<E> iteratorElements = new ArrayList<>();
    for (E element : collection) { // uses iterator()
      iteratorElements.add(element);
    }