testAddAndRemove(new ConcurrentHashMap<>());
  }

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

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