ImmutableList.of(2),
          ImmutableList.of(2, 3),
          ImmutableList.of(1, 2),
          ImmutableList.of(3, 5),
          ImmutableList.of(2, 4),
          ImmutableList.of(1, 2, 3, 5, 6, 8, 9));

  /*
   * We have a whole series of abstract test classes that "stack", so e.g. the tests for filtered
   * NavigableSets inherit the tests for filtered Iterables, Collections, Sets, and SortedSets. The