List<String> expected = emptyList();
    List<String> actual = Lists.newArrayList(filtered);
    assertEquals(expected, actual);
  }

  @GwtIncompatible // unreasonably slow
  public void testFilterUsingIteratorTester() {
    List<Integer> list = asList(1, 2, 3, 4, 5);
    Predicate<Integer> isEven =
        new Predicate<Integer>() {
          @Override
          public boolean apply(Integer integer) {