disjoint = new Target(disjointList, "disjoint");
    superset = new Target(MinimalCollection.of(e0(), e1(), e2(), e3(), e4()), "superset");
    nonEmptyProperSubset = new Target(MinimalCollection.of(e1()), "subset");
    sameElements = new Target(asList(createSamplesArray()), "sameElements");
    containsDuplicates =
        new Target(MinimalCollection.of(e0(), e0(), e3(), e3()), "containsDuplicates");

    int initialSize = collection.size();
    assertTrue("remove(present) should return true", collection.remove(e0()));
    assertEquals(
        "remove(present) should decrease a collection's size by one.",
        initialSize - 1,
        collection.size());
    expectMissing(e0());
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, FAILS_FAST_ON_CONCURRENT_MODIFICATION})
  @CollectionSize.Require(SEVERAL)

  public void testAddAll_withDuplicates() {
    MinimalCollection<E> elementsToAdd = MinimalCollection.of(e0(), e1(), e0(), e1());
    assertTrue("addAll(hasDuplicates) should return true", getList().addAll(elementsToAdd));
    expectAdded(e0(), e1(), e0(), e1());
  }

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testElementSetReflectsRemove() {
    Set<E> elementSet = getMultiset().elementSet();
    assertTrue(elementSet.contains(e0()));
    getMultiset().removeAll(singleton(e0()));
    assertFalse(elementSet.contains(e0()));
  }

  @CollectionSize.Require(absent = ZERO)
  @CollectionFeature.Require(SUPPORTS_REMOVE)
  public void testElementSetRemovePropagatesToMultiset() {

    assertEquals("size1Queue.poll() should return first element", e0(), getQueue().poll());
    expectMissing(e0());
  }

  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)
  public void testPoll_sizeMany() {
    assertEquals("sizeManyQueue.poll() should return first element", e0(), getQueue().poll());
    expectMissing(e0());
  }

    assertEquals("size1Queue.remove() should return first element", e0(), getQueue().remove());
    expectMissing(e0());
  }

  @CollectionFeature.Require({KNOWN_ORDER, SUPPORTS_REMOVE})
  @CollectionSize.Require(SEVERAL)
  public void testRemove_sizeMany() {
    assertEquals("sizeManyQueue.remove() should return first element", e0(), getQueue().remove());
    expectMissing(e0());
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedPresent() {
    assertTrue("add(present) should return true", getList().add(e0()));
    expectAdded(e0());
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)
  /*
   * absent = ZERO isn't required, since unmodList.add() must

    assertTrue(
        "addAll(somePresent) should return true",
        collection.addAll(MinimalCollection.of(e3(), e0())));
    assertTrue("should contain " + e3(), collection.contains(e3()));
    assertTrue("should contain " + e0(), collection.contains(e0()));
  }

  @CollectionFeature.Require(absent = SUPPORTS_ADD)
  @CollectionSize.Require(absent = ZERO)
  public void testAddAll_unsupportedSomePresent() {

    disjoint = new Target(disjointList, "disjoint");
    superset = new Target(MinimalCollection.of(e0(), e1(), e2(), e3(), e4()), "superset");
    nonEmptyProperSubset = new Target(MinimalCollection.of(e1()), "subset");
    sameElements = new Target(asList(createSamplesArray()), "sameElements");
    containsDuplicates =
        new Target(MinimalCollection.of(e0(), e0(), e3(), e3()), "containsDuplicates");

public class SampleElements<E extends @Nullable Object> implements Iterable<E> {
  // TODO: rename e3, e4 => missing1, missing2
  private final E e0;
  private final E e1;
  private final E e2;
  private final E e3;
  private final E e4;

  public SampleElements(E e0, E e1, E e2, E e3, E e4) {
    this.e0 = e0;
    this.e1 = e1;
    this.e2 = e2;
    this.e3 = e3;
    this.e4 = e4;
  }

  @Override