public void FindTest()
        {
            City.AllCities.Add(new City("NewYork"));
            City.AllCities.Add(new City("Saratov"));

            CityViewModel cityViewModel = new CityViewModel();

            cityViewModel.Find("new");

            int citiesInList = cityViewModel.Cities.Count();

            City.AllCities.Clear();

            Assert.IsTrue(citiesInList == 1);
        }