public void PurchaseItemsShouldReduceAccountBalance(int valueToAdd, string price, string value, int userQuantity) { //Arrange Accounting accounting = new Accounting(); CateringItem cateringItem = new CateringItem(); accounting.AddMoney(valueToAdd); decimal expected = decimal.Parse(value); cateringItem.Price = decimal.Parse(price); //Act //decimal result = accounting.SubtractPurchase(cateringItem, userQuantity); //Assert //Assert.AreEqual(expected, result); }