public void MultiplyCupWithCost() { //arrange Store store = new Store(); Cup cups = new Cup(); int cupsToBuy = 20; double cupCost = cups.GetCost(); double priceOfPurchasedcups = cupsToBuy * cupCost; double result; //act result = store.NumberOfCupsPurchased(cupsToBuy); //assert Assert.AreEqual(result, priceOfPurchasedcups); }