@CollectionSize.Require(absent = {ZERO, ONE})
  public void testRemoveAll_duplicate() {
    ArrayWithDuplicate<E> arrayAndDuplicate = createArrayWithDuplicateElement();
    collection = getSubjectGenerator().create(arrayAndDuplicate.elements);
    E duplicate = arrayAndDuplicate.duplicate;

    assertTrue(
        "removeAll(intersectingCollection) should return true",

  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testIndexOf_duplicate() {
    E[] array = createSamplesArray();
    array[getNumElements() / 2] = e0();
    collection = getSubjectGenerator().create(array);
    assertEquals(
        "indexOf(duplicate) should return index of first occurrence", 0, getList().indexOf(e0()));
  }

    int expectedHashCode = 0;
    for (E element : elements) {
      expectedHashCode += (element == null) ? 0 : element.hashCode();
    }

    elements.add(null);
    collection = getSubjectGenerator().create(elements.toArray());
    assertEquals(
        "A Set's hashCode() should be the sum of those of its elements (with "
            + "a null element counting as having a hash of zero).",
        expectedHashCode,

  @CollectionFeature.Require(value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedNullPresent() {
    E[] array = createArrayWithNullElement();
    collection = getSubjectGenerator().create(array);
    assertTrue("add(nullPresent) should return true", getList().add(null));

    List<E> expected = copyToList(array);
    expected.add(null);
    expectContents(expected);
  }

  /**

    entries.add(entryWithNull);

    int expectedHashCode = 0;
    for (Entry<K, V> entry : entries) {
      expectedHashCode += hash(entry);
    }

    resetContainer(getSubjectGenerator().create(entries.toArray()));
    assertEquals(
        "A Map's hashCode() should be the sum of those of its entries (where "
            + "a null element in an entry counts as having a hash of zero).",

  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testLastIndexOf_duplicate() {
    E[] array = createSamplesArray();
    array[getNumElements() / 2] = e0();
    collection = getSubjectGenerator().create(array);
    assertEquals(
        "lastIndexOf(duplicate) should return index of last occurrence",
        getNumElements() / 2,
        getList().lastIndexOf(e0()));
  }

  @CollectionFeature.Require(value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedNullPresent() {
    E[] array = createArrayWithNullElement();
    collection = getSubjectGenerator().create(array);
    assertTrue("add(nullPresent) should return true", getList().add(null));

    List<E> expected = copyToList(array);
    expected.add(null);
    expectContents(expected);
  }

  /**

public class AbstractMultisetTester<E> extends AbstractCollectionTester<E> {
  protected final Multiset<E> getMultiset() {
    return (Multiset<E>) collection;
  }

  protected void initThreeCopies() {
    collection = getSubjectGenerator().create(e0(), e0(), e0());
  }

  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testRemove_duplicate() {
    ArrayWithDuplicate<E> arrayAndDuplicate = createArrayWithDuplicateElement();
    collection = getSubjectGenerator().create(arrayAndDuplicate.elements);
    E duplicate = arrayAndDuplicate.duplicate;

    int firstIndex = getList().indexOf(duplicate);
    int initialSize = getList().size();

  @CollectionFeature.Require(value = {SUPPORTS_ADD, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testAdd_supportedNullPresent() {
    E[] array = createArrayWithNullElement();
    collection = getSubjectGenerator().create(array);
    assertFalse("add(nullPresent) should return false", getSet().add(null));
    expectContents(array);
  }

  /**