assertSame(STRING_LENGTH, set.comparator());
  }

  // TODO(b/172823566): Use mainline testToImmutableSortedSet once CollectorTester is usable.
  public void testToImmutableSortedSet_java7() {
    // Note that a Collector should generally enforce consistent comparator between builders
    ImmutableSortedSet.Builder<String> zis =
        ImmutableSortedSet.<String>naturalOrder().add("c", "b", "c");