}

  public void testAddAndRemove_concurrentSkipListMap() throws Exception {
    testAddAndRemove(new ConcurrentSkipListMap<String, AtomicInteger>());
  }

  public void testAddAndRemove_mapMakerMap() throws Exception {
    MapMaker mapMaker = new MapMaker();
    // force MapMaker to use its own MapMakerInternalMap
    mapMaker.useCustomMap = true;
    testAddAndRemove(mapMaker.<String, AtomicInteger>makeMap());