assertFalse("addAll(nothing) should return false", collection.addAll(emptyCollection()));
    expectUnchanged();
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  public void testAddAll_unsupportedNothing() {
    try {
      assertFalse(
          "addAll(nothing) should return false or throw", collection.addAll(emptyCollection()));
    } catch (UnsupportedOperationException tolerated) {
    }

  private Target partialOverlap;
  private Target containsDuplicates;
  private Target nullSingleton;

  @Override
  public void setUp() throws Exception {
    super.setUp();

    empty = new Target(emptyCollection(), "empty");
    /*
     * We test that nullSingleton.retainAll(disjointList) does NOT throw a
     * NullPointerException when disjointList does not, so we can't use

    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() {
    return samples.e1();
  }