public void ShouldJoinTheList()
        {
            GenericListManager <City> listManager = new CityListManager();

            City city1 = new City("Karpacz");
            City city2 = new City("Waszyngton");
            City city3 = new City("Świebodzin");

            listManager.AddElement(city1);

            List <City> anotherList = new List <City>();

            anotherList.Add(city2);
            anotherList.Add(city3);

            listManager.JoinList(anotherList);

            //check that city from another list exists in main list after the join process
            bool result = listManager.CheckElementExists("Waszyngton");

            Assert.IsTrue(result);
        }
        public void ShouldJoinTheList()
        {
            GenericListManager<City> listManager = new CityListManager();

            City city1 = new City("Karpacz");
            City city2 = new City("Waszyngton");
            City city3 = new City("Świebodzin");

            listManager.AddElement(city1);

            List<City> anotherList = new List<City>();
            anotherList.Add(city2);
            anotherList.Add(city3);

            listManager.JoinList(anotherList);

            //check that city from another list exists in main list after the join process
            bool result = listManager.CheckElementExists("Waszyngton");

            Assert.IsTrue(result);
        }