public void AddBillTest() { Assert.AreEqual(0, dataService.GetAllBills().Count()); dataService.AddCar("Skoda", "Fabia", "Style", 210, "Silver Metalic", VehicleType.Small_car, FuelType.Petrol, Transmission.Manual); dataService.AddWarehouseItem(dataService.GetAllCars().First(), 10000); dataService.AddBill(dataService.GetAllWarehouseItems().First()); Assert.AreEqual(1, dataService.GetAllCars().Count()); }