public void Given_4A_And_1B_When_CheckOut_Is_Called_Then_It_Should_Return_210() { // Arrange _promotionEngine = new PromotionEngine(_unitPrice, _activePromotions); IDictionary <char, int> itemsToBeCheckOut = new Dictionary <char, int>() { { 'A', 4 }, { 'B', 1 } }; // Act var total = _promotionEngine.CheckOut(itemsToBeCheckOut); // Assert Assert.AreEqual(210, total, "Something wrong in calculation"); }