assertTrue(set.containsAll(Sets.newTreeSet()));
    assertTrue(set.containsAll(Sets.newTreeSet(asList("b"))));
    assertTrue(set.containsAll(Sets.newTreeSet(asList("a", "f"))));
    assertTrue(set.containsAll(Sets.newTreeSet(asList("a", "b", "f"))));
    assertFalse(set.containsAll(Sets.newTreeSet(asList("d"))));
    assertFalse(set.containsAll(Sets.newTreeSet(asList("z"))));

    verifySetContents(set, EMPTY_COLLECTION);
  }

  public void testNewTreeSetEmpty() {
    TreeSet<Integer> set = Sets.newTreeSet();
    verifySortedSetContents(set, EMPTY_COLLECTION, null);
  }

  public void testNewTreeSetEmptyDerived() {
    TreeSet<Derived> set = Sets.newTreeSet();
    assertTrue(set.isEmpty());
    set.add(new Derived("foo"));
    set.add(new Derived("bar"));

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.Lists.newArrayList;
import static com.google.common.collect.Sets.newHashSet;
import static com.google.common.collect.Sets.newTreeSet;
import static com.google.common.collect.testing.SampleElements.Strings.AFTER_LAST;
import static com.google.common.collect.testing.SampleElements.Strings.AFTER_LAST_2;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.collect.Lists.newArrayList;
import static com.google.common.collect.Sets.newHashSet;
import static com.google.common.collect.Sets.newTreeSet;
import static com.google.common.collect.testing.SampleElements.Strings.AFTER_LAST;
import static com.google.common.collect.testing.SampleElements.Strings.AFTER_LAST_2;

   * only when the resulting list may need further modification, or may contain {@code null}. The
   * input is not modified. The returned list is serializable and has random access.
   *
   * <p>Unlike {@link Sets#newTreeSet(Iterable)}, this method does not discard elements that are
   * duplicates according to the comparator. The sort performed is <i>stable</i>, meaning that such

   * only when the resulting list may need further modification, or may contain {@code null}. The
   * input is not modified. The returned list is serializable and has random access.
   *
   * <p>Unlike {@link Sets#newTreeSet(Iterable)}, this method does not discard elements that are
   * duplicates according to the comparator. The sort performed is <i>stable</i>, meaning that such

  }

  private static class SortedSetSupplier extends CountingSupplier<TreeSet<Integer>> {
    @Override
    public TreeSet<Integer> getImpl() {
      return Sets.newTreeSet(INT_COMPARATOR);
    }

    private static final long serialVersionUID = 0;
  }

  public void testNewSortedSetMultimap() {
    CountingSupplier<TreeSet<Integer>> factory = new SortedSetSupplier();