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()));

        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()));

              ?, ? extends OneSizeTestContainerGenerator<SetMultimap<K, V>, Entry<K, V>>>
          parentBuilder) {
    return SetTestSuiteBuilder.using(
            new MultimapGetGenerator<K, V>(parentBuilder.getSubjectGenerator()))
        .withFeatures(computeMultimapGetFeatures(parentBuilder.getFeatures()))
        .named(parentBuilder.getName() + ".get[key]")
        .suppressing(parentBuilder.getSuppressedTests())
        .createTestSuite();

    if (parentBuilder.getFeatures().contains(CollectionFeature.SERIALIZABLE)) {
      derivedSuites.add(
          MapTestSuiteBuilder.using(
                  new ReserializedMapGenerator<K, V>(parentBuilder.getSubjectGenerator()))
              .withFeatures(computeReserializedMapFeatures(parentBuilder.getFeatures()))
              .named(parentBuilder.getName() + " reserialized")
              .suppressing(parentBuilder.getSuppressedTests())

    // TODO(cpovirk): consider using this approach (derived suites instead of extension) in
    // ListTestSuiteBuilder, etc.?
    derived.add(
        MapTestSuiteBuilder.using(new MapGenerator<K, V>(parentBuilder.getSubjectGenerator()))
            .withFeatures(parentBuilder.getFeatures())
            .named(parentBuilder.getName() + " [Map]")
            .suppressing(parentBuilder.getSuppressedTests())

  @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.entryComparator(navigableMap.comparator()));

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

        .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()))

  @CollectionSize.Require(SEVERAL)
  public void testOrderingAffectsEqualsComparisons() {
    ListMultimap<K, V> multimap1 =
        getSubjectGenerator()
            .create(mapEntry(k0(), v0()), mapEntry(k0(), v1()), mapEntry(k0(), v0()));
    ListMultimap<K, V> multimap2 =
        getSubjectGenerator()
            .create(mapEntry(k0(), v1()), mapEntry(k0(), v0()), mapEntry(k0(), v0()));

  @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);
  }

  @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);
  }