@Override
    protected SortedSet<Integer> create(Integer[] elements) {
      return checkedCreate(nullCheckedTreeSet(elements));
    }
  }

  public static class ContiguousSetHeadsetGenerator extends AbstractContiguousSetGenerator {
    @Override
    protected SortedSet<Integer> create(Integer[] elements) {
      SortedSet<Integer> set = nullCheckedTreeSet(elements);

        TestSortedSetGenerator<E> delegate, Bound to, Bound from) {
      super(delegate, to, from);
    }

    @Override
    NavigableSet<E> createSubSet(SortedSet<E> sortedSet, E firstExclusive, E lastExclusive) {
      NavigableSet<E> set = (NavigableSet<E>) sortedSet;
      if (from == Bound.NO_BOUND && to == Bound.INCLUSIVE) {
        return set.headSet(lastInclusive, true);

    SortedSet<String> set = of("e", "a", "f", "b", "d", "c");
    SortedSet<String> subset = set.subSet("c", "e");
    SortedSet<String> copy = copyOf(subset);
    assertEquals(subset, copy);
  }

  public void testCopyOf_headSet() {
    SortedSet<String> set = of("e", "a", "f", "b", "d", "c");
    SortedSet<String> headset = set.headSet("d");
    SortedSet<String> copy = copyOf(headset);
    assertEquals(headset, copy);
  }

  public Test testsForTreeSetWithComparator() {
    return NavigableSetTestSuiteBuilder.using(
            new TestStringSortedSetGenerator() {
              @Override
              public SortedSet<String> create(String[] elements) {
                SortedSet<String> set = new TreeSet<>(arbitraryNullFriendlyComparator());
                Collections.addAll(set, elements);
                return set;
              }
            })

    @Override
    protected SortedSet<Integer> create(Integer[] elements) {
      return checkedCreate(nullCheckedTreeSet(elements));
    }
  }

  public static class ContiguousSetHeadsetGenerator extends AbstractContiguousSetGenerator {
    @Override
    protected SortedSet<Integer> create(Integer[] elements) {
      SortedSet<Integer> set = nullCheckedTreeSet(elements);

    for (Collection<V> valueCollection : multimap().asMap().values()) {
      SortedSet<V> valueSet = (SortedSet<V>) valueCollection;
      assertEquals(multimap().valueComparator(), valueSet.comparator());
    }
  }

  public void testAsMapGetImplementsSortedSet() {
    for (K key : multimap().keySet()) {
      SortedSet<V> valueSet = (SortedSet<V>) multimap().asMap().get(key);

        .testForwarding(
            SortedSet.class,
            new Function<SortedSet, SortedSet>() {
              @Override
              public SortedSet apply(SortedSet delegate) {
                return wrap(delegate);
              }
            });
  }

  public void testEquals() {
    SortedSet<String> set1 = ImmutableSortedSet.of("one");
    SortedSet<String> set2 = ImmutableSortedSet.of("two");

    ms.add("a", 1);
    ms.add("b", 3);
    ms.add("c", 2);
    ms.add("d", 1);
    ms.add("e", 3);
    ms.add("f", 2);

    SortedSet<String> elementSet = ms.elementSet();
    assertThat(elementSet).containsExactly("a", "b", "c", "d", "e", "f").inOrder();
    SortedSet<String> subset = elementSet.subSet("b", "f");
    assertThat(subset).containsExactly("b", "c", "d", "e").inOrder();

    assertTrue(subset.remove("c"));

  }

  private static boolean hasSameComparator(Iterable<?> elements, Comparator<?> comparator) {
    if (elements instanceof SortedSet) {
      SortedSet<?> sortedSet = (SortedSet<?>) elements;
      Comparator<?> comparator2 = sortedSet.comparator();
      return (comparator2 == null)
          ? comparator == Ordering.natural()
          : comparator.equals(comparator2);
    }
    return false;
  }

    for (Collection<V> valueCollection : multimap().asMap().values()) {
      SortedSet<V> valueSet = (SortedSet<V>) valueCollection;
      assertEquals(multimap().valueComparator(), valueSet.comparator());
    }
  }

  public void testAsMapGetImplementsSortedSet() {
    for (K key : multimap().keySet()) {
      SortedSet<V> valueSet = (SortedSet<V>) multimap().asMap().get(key);