Tester (int longSize, String initVisibility) { final Set<Integer> visibleNodes = parseSet(initVisibility); UpdatableIntToIntMap updatableIntToIntMap = createUpdatableIntToIntMap(integer -> visibleNodes.contains(integer), longSize); Tester tester = new Tester(updatableIntToIntMap, visibleNodes); assertEquals(initVisibility, tester.mapToString()); return tester; }