@Override
  public void setUp() throws Exception {
    super.setUp();
    sortedMultiset = (SortedMultiset<E>) getMultiset();
    entries =
        copyToList(
            getSubjectGenerator()
                .getSampleElements(getSubjectGenerator().getCollectionSize().getNumElements()));
    sort(entries, sortedMultiset.comparator());

    // some tests assume SEVERAL == 3
    if (entries.size() >= 1) {

    array[getNullLocation()] = null;
    return array;
  }

  protected void initCollectionWithNullElement() {
    E[] array = createArrayWithNullElement();
    resetContainer(getSubjectGenerator().create(array));
  }

  /**
   * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call
   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.

    array[getNullLocation()] = null;
    return array;
  }

  protected void initCollectionWithNullElement() {
    E[] array = createArrayWithNullElement();
    resetContainer(getSubjectGenerator().create(array));
  }

  /**
   * Equivalent to {@link #expectMissing(Object[]) expectMissing}{@code (null)} except that the call
   * to {@code contains(null)} is permitted to throw a {@code NullPointerException}.

  @SuppressWarnings("UndefinedEquals")
  private void assertCleared() {
    assertEquals(0, multimap().size());
    assertEmpty(multimap());
    assertEquals(multimap(), getSubjectGenerator().create());
    assertEmpty(multimap().entries());
    assertEmpty(multimap().asMap());
    assertEmpty(multimap().keySet());
    assertEmpty(multimap().keys());
    assertEmpty(multimap().values());

          Platform.format(
              "%s [collection size: %s]", name, collectionSize.toString().toLowerCase());
      OneSizeGenerator<T, E> oneSizeGenerator =
          new OneSizeGenerator<>(getSubjectGenerator(), (CollectionSize) collectionSize);
      Set<Feature<?>> oneSizeFeatures = copyToSet(features);
      oneSizeFeatures.add(collectionSize);
      Set<Method> oneSizeSuppressedTests = getSuppressedTests();

   */
  @SuppressWarnings("UndefinedEquals")
  public void testRetainAllPropagatesToMultimap() {
    multimap().entries().retainAll(singleton(mapEntry(k0(), v0())));
    assertEquals(getSubjectGenerator().create(mapEntry(k0(), v0())), multimap());
    assertEquals(1, multimap().size());
    assertTrue(multimap().containsEntry(k0(), v0()));
  }

  @CollectionSize.Require(ONE)

    expectUnchanged();
  }

  @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
  @CollectionSize.Require(absent = ZERO)
  public void testRemove_nullPresent() {
    collection = getSubjectGenerator().create(createArrayWithNullElement());

    int initialSize = collection.size();
    assertTrue("remove(null) should return true", collection.remove(null));
    assertEquals(

    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,

    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).",

  @ListFeature.Require(SUPPORTS_SET)
  public void testSet_replacingNull() {
    E[] elements = createSamplesArray();
    int i = aValidIndex();
    elements[i] = null;
    collection = getSubjectGenerator().create(elements);

    doTestSet(e3());
  }

  private void doTestSet(E newValue) {
    int index = aValidIndex();
    E initialValue = getList().get(index);
    assertEquals(