IteratorTester<Integer> tester =
        new IteratorTester<Integer>(
            4, MODIFIABLE, newArrayList(1, 2, 3), IteratorTester.KnownOrder.KNOWN_ORDER) {
          @Override
          protected Iterator<Integer> newTargetIterator() {
            return Lists.newArrayList(1, 2, 3, 4).iterator();
          }
        };
    assertFailure(tester);
  }

  public void testCanCatchDifferentContents() {

      List<String> list = Lists.newArrayList(elements);
      list.add("zzz");
      return ImmutableSortedSet.copyOf(list).headSet("zzy");
    }
  }

  public static class ImmutableSortedSetTailsetGenerator extends TestStringSortedSetGenerator {
    @Override
    protected SortedSet<String> create(String[] elements) {
      List<String> list = Lists.newArrayList(elements);
      list.add("\0");

    assertNextPermutation(newArrayList(3, 4, 2, 1), permutations);
    assertNextPermutation(newArrayList(3, 2, 4, 1), permutations);
    assertNextPermutation(newArrayList(3, 2, 1, 4), permutations);

    assertNextPermutation(newArrayList(2, 3, 1, 4), permutations);
    assertNextPermutation(newArrayList(2, 3, 4, 1), permutations);
    assertNextPermutation(newArrayList(2, 4, 3, 1), permutations);

    assertNextPermutation(newArrayList(3, 4, 2, 1), permutations);
    assertNextPermutation(newArrayList(3, 2, 4, 1), permutations);
    assertNextPermutation(newArrayList(3, 2, 1, 4), permutations);

    assertNextPermutation(newArrayList(2, 3, 1, 4), permutations);
    assertNextPermutation(newArrayList(2, 3, 4, 1), permutations);
    assertNextPermutation(newArrayList(2, 4, 3, 1), permutations);

    List<Integer> list3 = newArrayList(3);
    input.add(1, list3);

    assertEquals(asList(1, 2, 3, 4), newArrayList(result));
    assertEquals("[1, 2, 3, 4]", result.toString());
  }

  public void testConcatVarargs() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);
    List<Integer> list3 = newArrayList(7, 8);
    List<Integer> list4 = newArrayList(9);

    input.add(1, list3);

    assertEquals(asList(1, 2, 3, 4), newArrayList(result));
    assertEquals("[1, 2, 3, 4]", result.toString());
  }

  public void testConcatVarargs() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);
    List<Integer> list3 = newArrayList(7, 8);
    List<Integer> list4 = newArrayList(9);
    List<Integer> list5 = newArrayList(10);

    IteratorTester<Integer> tester =
        new IteratorTester<Integer>(
            4, MODIFIABLE, newArrayList(1, 2, 3), IteratorTester.KnownOrder.KNOWN_ORDER) {
          @Override
          protected Iterator<Integer> newTargetIterator() {
            return Lists.newArrayList(1, 2, 3, 4).iterator();
          }
        };
    assertFailure(tester);
  }

  public void testCanCatchDifferentContents() {

    assertEquals(Lists.newArrayList("a", "b"), list);
  }

  public void testCreation_threeElements() {
    List<String> list = ImmutableList.of("a", "b", "c");
    assertEquals(Lists.newArrayList("a", "b", "c"), list);
  }

  public void testCreation_fourElements() {
    List<String> list = ImmutableList.of("a", "b", "c", "d");
    assertEquals(Lists.newArrayList("a", "b", "c", "d"), list);
  }

            Lists.<@Nullable Integer>newArrayList(nullInt),
            Lists.<@Nullable Integer>newArrayList(1, null, 2),
            Lists.newArrayList(1, 1),
            Lists.newArrayList(1, 2),
            Lists.newArrayList(1),
            Lists.newArrayList(2),
            Lists.newArrayList(),
            null)
        .inOrder();
  }

  public void testNatural() {

            Lists.<@Nullable Integer>newArrayList(nullInt),
            Lists.<@Nullable Integer>newArrayList(1, null, 2),
            Lists.newArrayList(1, 1),
            Lists.newArrayList(1, 2),
            Lists.newArrayList(1),
            Lists.newArrayList(2),
            Lists.newArrayList(),
            null)
        .inOrder();
  }

  public void testNatural() {