BiPredicate<ImmutableSortedSet<String>, ImmutableSortedSet<String>> equivalence =
        (set1, set2) ->
            set1.equals(set2)
                && set1.asList().equals(set2.asList())
                && set1.comparator().equals(set2.comparator());
    ImmutableSortedSet<String> expected =
        ImmutableSortedSet.orderedBy(String.CASE_INSENSITIVE_ORDER).add("a", "B", "c", "d").build();

    assertThat(set1).containsExactly(LegacyComparable.Z);

    @SuppressWarnings("unchecked") // using a legacy comparable
    ImmutableSortedSet<LegacyComparable> set2 =
        ImmutableSortedSet.of(LegacyComparable.Z, LegacyComparable.Y);
    assertThat(set2).containsExactly(LegacyComparable.Y, LegacyComparable.Z);
  }

  public void testLegacyComparable_copyOf_collection() {
    ImmutableSortedSet<LegacyComparable> set =