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"))));

    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"))));

  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;
      }
    };

package com.google.common.collect.testing.google;

import static com.google.common.base.Preconditions.checkNotNull;
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;

                  }

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

    assertTrue(map.isEmpty());
    assertThat(map.get("five")).isNull();
  }

  private static class NonNavigableSortedSet extends ForwardingSortedSet<String> {
    private final SortedSet<String> delegate = Sets.newTreeSet();

    @Override
    protected SortedSet<String> delegate() {
      return delegate;
    }
  }

  public void testAsMapSorted() {
    SortedSet<String> strings = new NonNavigableSortedSet();