public void CanGetHomeChangeDates() { HomeState stateHolder = new HomeState(); DateTime date = new DateTime(2015, 01, 01); const string roomName = "bedroom"; const string furnitureName = "sofa"; stateHolder.CreateFurniture(furnitureName, roomName, date); var dates = stateHolder.GetHomeChangeDates(); Assert.IsNotNull(dates); Assert.AreEqual(1, dates.Count); Assert.AreEqual(date, dates.First()); DateTime anotherDate = new DateTime(2015, 01, 02); stateHolder.CreateFurniture(furnitureName, roomName, anotherDate); dates = stateHolder.GetHomeChangeDates(); Assert.IsNotNull(dates); Assert.AreEqual(2, dates.Count); Assert.IsTrue(dates.Contains(date)); Assert.IsTrue(dates.Contains(anotherDate)); }