MapFeature.ALLOWS_NULL_VALUES,
                MapFeature.ALLOWS_ANY_NULL_QUERIES)
            .createTestSuite());
    return suite;
  }

  private static final class TestMultimap<K, V> extends ForwardingSetMultimap<K, V>
      implements Serializable {
    final SetMultimap<K, V> delegate = HashMultimap.create();
    public final Object mutex = new Integer(1); // something Serializable

    @Override

                MapFeature.ALLOWS_NULL_VALUES,
                MapFeature.ALLOWS_ANY_NULL_QUERIES)
            .createTestSuite());
    return suite;
  }

  private static final class TestMultimap<K, V> extends ForwardingSetMultimap<K, V>
      implements Serializable {
    final SetMultimap<K, V> delegate = HashMultimap.create();
    public final Object mutex = new Integer(1); // something Serializable

    @Override