public static void CallHistoryTest() { GSMobile phone = new GSMobile("Galaxy S7", "Samsung", 949.99m, "Papa", new Battery("Removable", BatteryType.NiCd, 100, 11), new Display(6.5f, 16)); Console.WriteLine(phone.ToString()); phone.AddCall(DateTime.Now, "+35900472475", 583); phone.AddCall(DateTime.Now, "+9584635244757", 115); phone.AddCall(DateTime.Now, "+9583652758", 18); phone.CallHistoryView(); Console.WriteLine("The total prise is ${0:f2} ", phone.TotalPrice()); Call one = new Call(DateTime.Now, "+35900472475", 583); phone.RemoveCall(one); phone.CallHistoryView(); Console.WriteLine("The total prise after removing of one element is ${0:f2} ", phone.TotalPrice()); phone.ClearCallHistory(); phone.CallHistoryView(); Console.WriteLine("The total prise after clearing list is ${0:f2} ", phone.TotalPrice()); }