assertEquals(Ordering.natural(), multimap.valueComparator());
    SerializableTester.reserializeAndAssert(multimap);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testTreeMultimapNonGeneric() {
    TreeMultimap<LegacyComparable, LegacyComparable> multimap = TreeMultimap.create();
    assertEquals(ImmutableMultimap.of(), multimap);
    multimap.put(new LegacyComparable("foo"), new LegacyComparable("f"));