public void UpdateCityTests() { //Arrange CitySqlDAO dao = new CitySqlDAO(ConnectionString); IList <City> cities = dao.GetCitiesByCountryCode("USA"); City cityToUpdate = cities[0]; //Act cityToUpdate.Population = 5; dao.UpdateCity(cityToUpdate); //Assert Assert.AreEqual(5, cityToUpdate.Population); //THIS TEST IS ONLY TESTING MEMORY NOT THE DB IList <City> updatedCities = dao.GetCitiesByCountryCode("USA"); City fromDB = null; foreach (City c in updatedCities) { if (c.CityId == cityToUpdate.CityId) { fromDB = c; break; } } Assert.AreEqual(5, fromDB.Population); }