assertThrows(
        NullPointerException.class,
        () -> ImmutableListMultimap.copyOf((ArrayListMultimap<String, Integer>) input));
  }

  // TODO(b/172823566): Use mainline testToImmutableListMultimap once CollectorTester is usable.
  public void testToImmutableListMultimap_java7_combine() {
    ImmutableListMultimap.Builder<String, Integer> zis =

    assertThrows(
        NullPointerException.class,
        () -> ImmutableListMultimap.copyOf((ArrayListMultimap<String, Integer>) input));
  }

  public void testToImmutableListMultimap() {
    Collector<Entry<String, Integer>, ?, ImmutableListMultimap<String, Integer>> collector =
        toImmutableListMultimap(Entry::getKey, Entry::getValue);