iterator.remove();
      fail("UnsupportedOperationException expected");
    } catch (UnsupportedOperationException expected) {
    }
  }

  @GwtIncompatible // NavigableSet
  public void testSubSet_boundedRange() {
    ImmutableSortedSet<Integer> set = ImmutableSortedSet.of(2, 4, 6, 8, 10);
    ImmutableSortedSet<Integer> empty = ImmutableSortedSet.of();

    assertEquals(set, Sets.subSet(set, Range.closed(0, 12)));