public void CanApplyStrawberriesSpecialOfferToStrawbsTrolley_ShouldReturn22_50() { // arrange var checkout = new Checkout(_strawbsTrolley); //act var discountedTrolley = checkout.ApplyStrawberriesSpecialOffer(); var discountedTotal = checkout.GetTotal(); //assert Assert.AreNotEqual(discountedTrolley, null); Assert.AreEqual(discountedTrolley.Count(), 5); Assert.AreEqual(discountedTotal, 22.50); }