protected void verify(List<Integer> elements) {
        assertEquals(elements, new ArrayList<>(multimap.values()));
      }
    }.test();
  }

  @GwtIncompatible // unreasonably slow
  public void testKeySetIteration() {
    new IteratorTester<String>(
        6,
        MODIFIABLE,
        new LinkedHashSet<>(asList("foo", "bar", "baz", "dog", "cat")),
        IteratorTester.KnownOrder.KNOWN_ORDER) {