public void slotNumberForRegNo_NegTest() { Car[] cars = new Car[3] { new Car { Color = "white", RegistrationNumber = "KA-01-HH-1234", SlotNumber = 1 }, new Car { Color = "red", RegistrationNumber = "KA-01-HH-9876", SlotNumber = 2 }, new Car { Color = "blue", RegistrationNumber = "KA-01-KH-1762", SlotNumber = 3 } }; sampleLot = new Model.ParkingLot(4) { Cars = cars }; ICommands commands = new CommandRouter(); Program.ParkingLot = sampleLot; int slotNo = commands.slot_number_for_registration_number("KA-01-HH-0000"); Assert.IsTrue(slotNo == -1); }