assertEquals(asList(1, 4, 7, 8, 9, 10), newArrayList(result));
    assertEquals("[1, 4, 7, 8, 9, 10]", result.toString());
  }

  public void testConcatNullPointerException() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);

    try {
      FluentIterable.concat(list1, null, list2);
      fail();

    List<@Nullable Integer> list1 = Lists.newArrayList();
    List<@Nullable Integer> list2 = Lists.newArrayList(1);
    List<@Nullable Integer> list3 = Lists.newArrayList(1, 1);
    List<@Nullable Integer> list4 = Lists.newArrayList(1, 2);
    List<@Nullable Integer> list5 = Lists.newArrayList(1, null, 2);
    List<@Nullable Integer> list6 = Lists.newArrayList(2);

    List<@Nullable Integer> list1 = Lists.newArrayList();
    List<@Nullable Integer> list2 = Lists.newArrayList(1);
    List<@Nullable Integer> list3 = Lists.newArrayList(1, 1);
    List<@Nullable Integer> list4 = Lists.newArrayList(1, 2);
    List<@Nullable Integer> list5 = Lists.newArrayList(1, null, 2);
    List<@Nullable Integer> list6 = Lists.newArrayList(2);

    assertEquals(asList(1, 4, 7, 8, 9, 10), newArrayList(result));
    assertEquals("[1, 4, 7, 8, 9, 10]", result.toString());
  }

  public void testConcatNullPointerException() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);

    try {
      Iterables.concat(list1, null, list2);
      fail();
    } catch (NullPointerException expected) {

cpovirk <******@****.***> 1510351134 -0800

        .testForwarding(
            List.class,
            new Function<List, List>() {
              @Override
              public List apply(List delegate) {
                return wrap(delegate);
              }
            });
  }

  public void testEquals() {
    List<String> list1 = ImmutableList.of("one");
    List<String> list2 = ImmutableList.of("two");
    new EqualsTester()

    assertEquals(asList(1, 4, 7, 8, 9, 10), newArrayList(result));
    assertEquals("[1, 4, 7, 8, 9, 10]", result.toString());
  }

  public void testConcatNullPointerException() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);

    try {
      FluentIterable.concat(list1, null, list2);
      fail();

        .addEqualityGroup(newDelegatingIterableWithEquals(LIST2)) // different interface
        .testEquals();
  }

  @SuppressWarnings("unchecked") // proxy of List<String>
  private static List<String> newDelegatingList(List<String> delegate) {
    return Reflection.newProxy(List.class, new DelegatingInvocationHandler(delegate));
  }

  @SuppressWarnings("unchecked") // proxy of List<String>

    assertThat(Lists.hashCodeImpl(base)).isNotEqualTo(Lists.hashCodeImpl(outOfOrder));
    assertThat(Lists.hashCodeImpl(base)).isNotEqualTo(Lists.hashCodeImpl(diffValue));
    assertThat(Lists.hashCodeImpl(base)).isNotEqualTo(Lists.hashCodeImpl(diffLength));
    assertThat(Lists.hashCodeImpl(base)).isNotEqualTo(Lists.hashCodeImpl(empty));
  }

  public void testEqualsImpl() {

    assertEquals(list, newArrayList(Iterators.limit(list.iterator(), 1)));
    assertEquals(list, newArrayList(Iterators.limit(list.iterator(), 2)));

    list.add("pants");
    assertFalse(Iterators.limit(list.iterator(), 0).hasNext());
    assertEquals(ImmutableList.of("cool"), newArrayList(Iterators.limit(list.iterator(), 1)));
    assertEquals(list, newArrayList(Iterators.limit(list.iterator(), 2)));