@Override
    protected SortedSet<String> create(String[] elements) {
      List<String> list = Lists.newArrayList(elements);
      list.add("\0");
      return ImmutableSortedSet.copyOf(list).tailSet("\0\0");
    }
  }

  public static class ImmutableSortedSetSubsetGenerator extends TestStringSortedSetGenerator {
    @Override
    protected SortedSet<String> create(String[] elements) {

    }

    @Override
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
      synchronized (mutex) {
        return Synchronized.navigableSet(delegate().tailSet(fromElement, inclusive), mutex);
      }
    }

    @Override
    public SortedSet<E> tailSet(E fromElement) {
      return tailSet(fromElement, true);
    }

      return standardPollLast();
    }

    @Override
    public SortedSet<T> headSet(T toElement) {
      return standardHeadSet(toElement);
    }

    @Override
    public SortedSet<T> tailSet(T fromElement) {
      return standardTailSet(fromElement);
    }
  }

  @AndroidIncompatible // test-suite builders
  public static Test suite() {
    TestSuite suite = new TestSuite();

    }

    @Override
    public NavigableSet<E> tailSet(E fromElement, boolean inclusive) {
      synchronized (mutex) {
        return Synchronized.navigableSet(delegate().tailSet(fromElement, inclusive), mutex);
      }
    }

    @Override
    public SortedSet<E> tailSet(E fromElement) {
      return tailSet(fromElement, true);
    }

    @Override
    protected SortedSet<String> create(String[] elements) {
      List<String> list = Lists.newArrayList(elements);
      list.add("\0");
      return ImmutableSortedSet.copyOf(list).tailSet("\0\0");
    }
  }

  public static class ImmutableSortedSetSubsetGenerator extends TestStringSortedSetGenerator {
    @Override
    protected SortedSet<String> create(String[] elements) {

            .build();
    assertTrue(set.tailSet("california") instanceof ImmutableSortedSet);
    assertTrue(set.tailSet("fish") instanceof ImmutableSortedSet);
    assertThat(set.tailSet("fish")).containsExactly("over", "quick", "jumped").inOrder();
    assertThat(set.tailSet("a"))
        .containsExactly("a", "in", "the", "over", "quick", "jumped")
        .inOrder();
    assertTrue(set.tailSet("california").isEmpty());
  }

  public void testEmptySubSet() {
    NavigableSet<E> empty = navigableSet.subSet(e0(), false, e0(), false);
    assertEquals(new TreeSet<E>(), empty);
  }

  /*
   * TODO(cpovirk): more testing of subSet/headSet/tailSet/descendingSet? and/or generate derived
   * suites?
   */

  /**
   * Returns the {@link Method} instances for the test methods in this class that create a set with

  public void testEmptySubSet() {
    NavigableSet<E> empty = navigableSet.subSet(e0(), false, e0(), false);
    assertEquals(new TreeSet<E>(), empty);
  }

  /*
   * TODO(cpovirk): more testing of subSet/headSet/tailSet/descendingSet? and/or generate derived
   * suites?
   */

  /**
   * Returns the {@link Method} instances for the test methods in this class that create a set with

      }

      @Override
      public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
        return removeOnlySortedSet(super.tailSet(fromElement));
      }

      @Override
      public NavigableSet<E> tailSet(@ParametricNullness E fromElement, boolean inclusive) {
        return removeOnlyNavigableSet(super.tailSet(fromElement, inclusive));
      }

      @Override

      }

      @Override
      public SortedSet<E> tailSet(@ParametricNullness E fromElement) {
        return removeOnlySortedSet(super.tailSet(fromElement));
      }

      @Override
      public NavigableSet<E> tailSet(@ParametricNullness E fromElement, boolean inclusive) {
        return removeOnlyNavigableSet(super.tailSet(fromElement, inclusive));
      }

      @Override