UnsupportedOperationException.class,
        () -> multimap().putAll(getSubjectGenerator().create(mapEntry(k3(), v3()))));
  }

  @MapFeature.Require(SUPPORTS_PUT)
  // Empty multimaps *do* have defined equals semantics.
  @SuppressWarnings("UndefinedEquals")
  public void testPutAllIntoEmpty() {
    Multimap<K, V> target = getSubjectGenerator().create();
    assertEquals(!multimap().isEmpty(), target.putAll(multimap()));

    new EqualsTester()
        .addEqualityGroup(
            getMultiset(), getSubjectGenerator().create(getSampleElements().toArray()))
        .testEquals();
  }

  @CollectionSize.Require(absent = ZERO)
  public void testNotEqualsEmpty() {
    new EqualsTester()
        .addEqualityGroup(getMultiset())
        .addEqualityGroup(getSubjectGenerator().create())
        .testEquals();
  }

    }
  }

  protected E[] createSamplesArray() {
    E[] array = getSubjectGenerator().createArray(getNumElements());
    getSampleElements().toArray(array);
    return array;
  }

  protected E[] createOrderedArray() {
    E[] array = getSubjectGenerator().createArray(getNumElements());
    getOrderedElements().toArray(array);
    return array;
  }

  @Override
  public void setUp() throws Exception {
    super.setUp();
    navigableMap = (SortedMap<K, V>) getMap();
    List<Entry<K, V>> entries =
        copyToList(
            getSubjectGenerator()
                .getSampleElements(getSubjectGenerator().getCollectionSize().getNumElements()));
    sort(entries, Helpers.<K, V>entryComparator(navigableMap.comparator()));

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

  public void testRemovingIteratorKnownOrder() {
    new IteratorTester<E>(
        4,
        MODIFIABLE,
        getSubjectGenerator().order(asList(e0(), e1(), e1(), e2())),
        IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override
      protected Iterator<E> newTargetIterator() {
        return getSubjectGenerator().create(e0(), e1(), e1(), e2()).iterator();
      }
    }.test();
  }

  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testCreateWithDuplicates_nullDuplicatesNotRejected() {
    E[] array = createArrayWithNullElement();
    array[0] = null;
    collection = getSubjectGenerator().create(array);

    List<E> expectedWithDuplicateRemoved = asList(array).subList(1, getNumElements());
    expectContents(expectedWithDuplicateRemoved);
  }

        .addEqualityGroup(multimap(), getSubjectGenerator().create(getSampleElements().toArray()))
        .testEquals();
  }

  public void testEqualsFalse() {
    List<Entry<K, V>> targetEntries = new ArrayList<>(getSampleElements());
    targetEntries.add(mapEntry(k0(), v3()));
    new EqualsTester()
        .addEqualityGroup(multimap())
        .addEqualityGroup(getSubjectGenerator().create(targetEntries.toArray()))

  @CollectionFeature.Require(SUPPORTS_REMOVE)
  @CollectionSize.Require(absent = {ZERO, ONE})
  public void testRetainAll_duplicatesKept() {
    E[] array = createSamplesArray();
    array[1] = e0();
    collection = getSubjectGenerator().create(array);
    assertFalse(
        "containsDuplicates.retainAll(superset) should return false",
        collection.retainAll(MinimalCollection.of(createSamplesArray())));
    expectContents(array);
  }

    }
  }

  protected E[] createSamplesArray() {
    E[] array = getSubjectGenerator().createArray(getNumElements());
    getSampleElements().toArray(array);
    return array;
  }

  protected E[] createOrderedArray() {
    E[] array = getSubjectGenerator().createArray(getNumElements());
    getOrderedElements().toArray(array);
    return array;
  }

    new EqualsTester()
        .addEqualityGroup(
            getMultiset(), getSubjectGenerator().create(getSampleElements().toArray()))
        .testEquals();
  }

  @CollectionSize.Require(absent = ZERO)
  public void testNotEqualsEmpty() {
    new EqualsTester()
        .addEqualityGroup(getMultiset())
        .addEqualityGroup(getSubjectGenerator().create())
        .testEquals();
  }