SortedSet<String> subset = elementSet.subSet("b", "f");
    assertThat(subset).containsExactly("b", "c", "d", "e").inOrder();

    assertTrue(subset.remove("c"));
    assertThat(elementSet).containsExactly("a", "b", "d", "e", "f").inOrder();
    assertThat(subset).containsExactly("b", "d", "e").inOrder();
    assertEquals(10, ms.size());

    assertFalse(subset.remove("a"));

    assertThat(set.subSet(1, 4)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.subSet(2, 4)).containsExactly(2, 3).inOrder();
    assertThat(set.subSet(3, 4)).containsExactly(3).inOrder();
    assertThat(set.subSet(3, 3)).isEmpty();
    assertThat(set.subSet(2, 3)).containsExactly(2).inOrder();
    assertThat(set.subSet(1, 3)).containsExactly(1, 2).inOrder();

    SortedSet<String> set = of("e");
    assertTrue(set.subSet("c", "g") instanceof ImmutableSortedSet);
    assertThat(set.subSet("c", "g")).contains("e");
    assertThat(set.subSet("e", "g")).contains("e");
    assertSame(this.<String>of(), set.subSet("f", "g"));
    assertSame(this.<String>of(), set.subSet("c", "e"));
    assertSame(this.<String>of(), set.subSet("c", "d"));
  }

  public void testSingle_first() {

    SortedSet<String> subset = elementSet.subSet("b", "f");
    assertThat(subset).containsExactly("b", "c", "d", "e").inOrder();

    assertTrue(subset.remove("c"));
    assertThat(elementSet).containsExactly("a", "b", "d", "e", "f").inOrder();
    assertThat(subset).containsExactly("b", "d", "e").inOrder();
    assertEquals(10, ms.size());

    assertFalse(subset.remove("a"));

    assertThat(set.subSet(1, 4)).containsExactly(1, 2, 3).inOrder();
    assertThat(set.subSet(2, 4)).containsExactly(2, 3).inOrder();
    assertThat(set.subSet(3, 4)).containsExactly(3).inOrder();
    assertThat(set.subSet(3, 3)).isEmpty();
    assertThat(set.subSet(2, 3)).containsExactly(2).inOrder();
    assertThat(set.subSet(1, 3)).containsExactly(1, 2).inOrder();

    SortedSet<String> set = of("e");
    assertTrue(set.subSet("c", "g") instanceof ImmutableSortedSet);
    assertThat(set.subSet("c", "g")).contains("e");
    assertThat(set.subSet("e", "g")).contains("e");
    assertSame(this.<String>of(), set.subSet("f", "g"));
    assertSame(this.<String>of(), set.subSet("c", "e"));
    assertSame(this.<String>of(), set.subSet("c", "d"));
  }

  public void testSingle_first() {

                    set.addAll(difference);
                    Set<String> subset = newHashSet(samples());
                    subset.removeAll(difference);
                    return difference(set, subset);
                  }
                })
            .named("set - subset")
            .withFeatures(

         * greater than tooHigh.
         */
        return ContiguousSet.create(Range.openClosed(0, 1), DiscreteDomain.integers()).subSet(0, 1);
      }
      int tooHigh = set.last() + 1;
      int tooLow = set.first() - 1;
      set.add(tooHigh);
      set.add(tooLow);
      return checkedCreate(set).subSet(tooLow + 1, tooHigh);
    }
  }

  @GwtIncompatible // NavigableSet

    }

    @Override
    public NavigableSet<E> subSet(
        @ParametricNullness E fromElement,
        boolean fromInclusive,
        @ParametricNullness E toElement,
        boolean toInclusive) {
      return forward.subSet(toElement, toInclusive, fromElement, fromInclusive).descendingSet();
    }

    @Override
    public SortedSet<E> subSet(@ParametricNullness E fromElement, @ParametricNullness E toElement) {

    }

    @Override
    public NavigableSet<K> subSet(
        @ParametricNullness K fromElement, @ParametricNullness K toElement) {
      return subSet(fromElement, true, toElement, false);
    }

    @Override
    public NavigableSet<K> subSet(
        @ParametricNullness K fromElement,
        boolean fromInclusive,