() -> {
          ImmutableListMultimap<String, Integer> unused =
              fluent(1, null, 2).index(Functions.constant("foo"));
        });
  }

  public void testUniqueIndex() {
    ImmutableMap<Integer, String> expected = ImmutableMap.of(3, "two", 5, "three", 4, "four");
    ImmutableMap<Integer, String> index =
        FluentIterable.from(asList("two", "three", "four"))