public static void CallHistoryTest()
{
Gsm test2 = new Gsm("3310", "Nokia", 50.5M, "Gosho", new Battery("12345EN", 50, 30, BatteryType.Nickel_Cadmium), new Display(2.2, 16));
test2.AddCall("13.03.2010", "16:10", "15429580239", 582);
test2.AddCall("12.04.2011", "11:22", "31235513132", 1318);
test2.AddCall("09.11.2012", "20:55", "65426527474", 310);
Console.WriteLine(test2.CallHistory);
Console.WriteLine(test2.GetTotalPrice());
test2.DeleteLongestCall();
Console.WriteLine(test2.GetTotalPrice());
test2.DeleteAllCalls();
Console.WriteLine(test2.GetTotalPrice());
}