public void testSameComparator() {
    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Sets.newTreeSet()));
    assertTrue(SortedIterables.hasSameComparator(Ordering.natural(), Maps.newTreeMap().keySet()));
    assertTrue(
        SortedIterables.hasSameComparator(
            Ordering.natural().reverse(), Sets.newTreeSet(Ordering.natural().reverse())));
  }

  public void testComparator() {

@NullUnmarked
public final class SetsFilterNavigableSetTest extends AbstractFilteredNavigableSetTest {
  @Override
  NavigableSet<Integer> createUnfiltered(Iterable<Integer> contents) {
    return Sets.newTreeSet(contents);
  }

  @Override
  NavigableSet<Integer> filter(
      NavigableSet<Integer> elements, Predicate<? super Integer> predicate) {
    return Sets.filter(elements, predicate);
  }

                  }

                  @Override
                  public List<String> order(List<String> insertionOrder) {
                    return new ArrayList<>(Sets.newTreeSet(insertionOrder));
                  }
                })
            .withFeatures(
                CollectionSize.ANY,
                CollectionFeature.KNOWN_ORDER,
                CollectionFeature.GENERAL_PURPOSE)

                  }

                  @Override
                  public List<String> order(List<String> insertionOrder) {
                    return new ArrayList<>(Sets.newTreeSet(insertionOrder));
                  }
                })
            .named("ForwardingNavigableSet[SafeTreeSet] with standard implementations")
            .withFeatures(
                CollectionSize.ANY,

@NullUnmarked
public final class SetsFilterSortedSetTest
    extends AbstractFilteredSortedSetTest<SortedSet<Integer>> {
  @Override
  SortedSet<Integer> createUnfiltered(Iterable<Integer> contents) {
    TreeSet<Integer> result = Sets.newTreeSet(contents);
    // we have to make the result not Navigable
    return new ForwardingSortedSet<Integer>() {
      @Override
      protected SortedSet<Integer> delegate() {
        return result;
      }
    };

                  }

                  @Override
                  public List<String> order(List<String> insertionOrder) {
                    return new ArrayList<>(Sets.newTreeSet(insertionOrder));
                  }
                })
            .named("ForwardingSortedSet[SafeTreeSet] with standard implementations")
            .withFeatures(
                CollectionSize.ANY,