builder.put(elements[i], i);
      }
      return builder.build().keySet().asList();
    }

    @Override
    public List<String> order(List<String> insertionOrder) {
      return Ordering.<String>natural().sortedCopy(insertionOrder);
    }
  }

  public static class ImmutableSortedMapValueListGenerator extends TestStringListGenerator {
    @Override
    protected List<String> create(String[] elements) {

   */
  @Override
  Map<K, Collection<V>> asMap();

  /**
   * Returns the comparator that orders the multimap values, with {@code null} indicating that
   * natural ordering is used.
   */
  @Nullable Comparator<? super V> valueComparator();

    @Override
    public Integer[] createArray(int length) {
      return new Integer[length];
    }

    @Override
    public Iterable<Integer> order(List<Integer> insertionOrder) {
      return Ordering.natural().sortedCopy(insertionOrder);
    }

    @Override
    public Set<Integer> create(Object... elements) {
      ImmutableRangeSet.Builder<Integer> builder = ImmutableRangeSet.builder();
      for (Object o : elements) {

      Iterable<Iterable<Integer>> iterables, Iterable<Integer> unsortedExpected) {
    Iterable<Integer> expected = Ordering.<Integer>natural().sortedCopy(unsortedExpected);

    Iterable<Integer> mergedIterator = mergeSorted(iterables, Ordering.natural());

    assertEquals(Lists.newLinkedList(expected), Lists.newLinkedList(mergedIterator));
  }

  }

  public void testOrderedPermutationSetRepeatedElements() {
    List<Integer> list = newArrayList(1, 1, 2, 2);
    Iterator<List<Integer>> permutations =
        Collections2.orderedPermutations(list, Ordering.natural()).iterator();

    assertNextPermutation(newArrayList(1, 1, 2, 2), permutations);
    assertNextPermutation(newArrayList(1, 2, 1, 2), permutations);
    assertNextPermutation(newArrayList(1, 2, 2, 1), permutations);

    }

    /** Sorts the elements in reverse natural order. */
    @SuppressWarnings("CanIgnoreReturnValueSuggester") // see ImmutableSortedSetExplicitComparator
    @Override
    public List<Integer> order(List<Integer> insertionOrder) {
      sort(insertionOrder, Ordering.<Integer>natural().reverse());
      return insertionOrder;
    }
  }

        for (int i = 0; i < objectsNum; i++) {
          objects.add(new Object());
        }

        Iterable<?> locks = striped.bulkGet(objects);
        assertTrue(Ordering.natural().onResultOf(Functions.forMap(indexByLock)).isOrdered(locks));

        // check idempotency
        Iterable<?> locks2 = striped.bulkGet(objects);
        assertEquals(Lists.newArrayList(locks), Lists.newArrayList(locks2));

        for (int i = 0; i < objectsNum; i++) {
          objects.add(new Object());
        }

        Iterable<?> locks = striped.bulkGet(objects);
        assertTrue(Ordering.natural().onResultOf(Functions.forMap(indexByLock)).isOrdered(locks));

        // check idempotency
        Iterable<?> locks2 = striped.bulkGet(objects);
        assertEquals(Lists.newArrayList(locks), Lists.newArrayList(locks2));

                  }

                  @Override
                  public List<String> order(List<String> insertionOrder) {
                    return Ordering.natural().sortedCopy(insertionOrder);
                  }
                })
            .named("ForwardingSortedMultiset with standard impls")
            .withFeatures(
                CollectionSize.ANY,

  // Map from sample string lengths to the fingerprint
  private static final ImmutableSortedMap<Integer, Long> LENGTH_FINGERPRINTS =
      new ImmutableSortedMap.Builder<Integer, Long>(Ordering.natural())
          .put(1000, 0x433109b33e13e6edL)
          .put(800, 0x5f2f123bfc815f81L)
          .put(640, 0x6396fc6a67293cf4L)
          .put(512, 0x45c01b4934ddbbbeL)
          .put(409, 0xfcd19b617551db45L)