@GwtCompatible
@NullMarked
public class MinimalCollection<E extends @Nullable Object> extends AbstractCollection<E> {
  // TODO: expose allow nulls parameter?

  public static <E extends @Nullable Object> MinimalCollection<E> of(E... contents) {
    return new MinimalCollection<>(Object.class, true, contents);
  }

  // TODO: use this
  public static <E extends @Nullable Object> MinimalCollection<E> ofClassAndContents(

@GwtCompatible
@NullMarked
public class MinimalCollection<E extends @Nullable Object> extends AbstractCollection<E> {
  // TODO: expose allow nulls parameter?

  public static <E extends @Nullable Object> MinimalCollection<E> of(E... contents) {
    return new MinimalCollection<>(Object.class, true, contents);
  }

  // TODO: use this
  public static <E extends @Nullable Object> MinimalCollection<E> ofClassAndContents(

                  protected Collection<String> create(String[] elements) {
                    return new StandardImplForwardingCollection<>(MinimalCollection.of(elements));
                  }
                })
            .named("ForwardingCollection[MinimalCollection] with standard implementations")
            .withFeatures(CollectionSize.ANY, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

   */
  protected int getNullLocation() {
    return getNumElements() / 2;
  }

  protected MinimalCollection<E> createDisjointCollection() {
    return MinimalCollection.of(e3(), e4());
  }

  protected MinimalCollection<E> emptyCollection() {
    return MinimalCollection.of();
  }

  protected final E e0() {
    return samples.e0();
  }

  protected final E e1() {

                  protected Collection<String> create(String[] elements) {
                    return new StandardImplForwardingCollection<>(MinimalCollection.of(elements));
                  }
                })
            .named("ForwardingCollection[MinimalCollection] with standard implementations")
            .withFeatures(CollectionSize.ANY, CollectionFeature.ALLOWS_NULL_VALUES)
            .createTestSuite());

   */
  protected int getNullLocation() {
    return getNumElements() / 2;
  }

  protected MinimalCollection<E> createDisjointCollection() {
    return MinimalCollection.of(e3(), e4());
  }

  protected MinimalCollection<E> emptyCollection() {
    return MinimalCollection.of();
  }

  protected final E e0() {
    return samples.e0();
  }

  protected final E e1() {

     * MinimalCollection, which throws NullPointerException on calls to
     * contains(null).
     */
    List<E> disjointList = asList(e3(), e4());
    disjoint = new Target(disjointList, "disjoint");
    superset = new Target(MinimalCollection.of(e0(), e1(), e2(), e3(), e4()), "superset");
    nonEmptyProperSubset = new Target(MinimalCollection.of(e1()), "subset");

     * MinimalCollection, which throws NullPointerException on calls to
     * contains(null).
     */
    List<E> disjointList = asList(e3(), e4());
    disjoint = new Target(disjointList, "disjoint");
    superset = new Target(MinimalCollection.of(e0(), e1(), e2(), e3(), e4()), "superset");
    nonEmptyProperSubset = new Target(MinimalCollection.of(e1()), "subset");

  }

  public void testCopyOf_collection_empty() {
    Collection<String> c = MinimalCollection.of();
    List<String> list = ImmutableList.copyOf(c);
    assertEquals(emptyList(), list);
  }

  public void testCopyOf_collection_oneElement() {
    Collection<String> c = MinimalCollection.of("a");
    List<String> list = ImmutableList.copyOf(c);
    assertEquals(singletonList("a"), list);
  }

  }

  public void testCopyOf_collection_empty() {
    Collection<String> c = MinimalCollection.of();
    List<String> list = ImmutableList.copyOf(c);
    assertEquals(emptyList(), list);
  }

  public void testCopyOf_collection_oneElement() {
    Collection<String> c = MinimalCollection.of("a");
    List<String> list = ImmutableList.copyOf(c);
    assertEquals(singletonList("a"), list);
  }