public void If_MultiPriceRule_A_3_130_And_MultiPriceRule_A_5_190_And_Scan_9A_Then_Price_is_370()
        {
            IPricingEngine pe = new PricingEngine(
                new List<IPricingRule> {
                    new QuantityPricingRule("A", 50),
                    new QuantityPricingRule("A", 3, 130),
                    new QuantityPricingRule("A", 5, 190),
                });

            ICheckout co = new Checkout(pe);

            for (int i = 0; i < 9; i++)
            {
                co.Scan("A");
            }

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 370;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_MultiPriceRule_B_2_45_And_MultiPriceRule_A_3_130_And_Scan_AAABBD_Then_Price_is_190()
        {
            IPricingEngine pe = new PricingEngine();
            pe.AddQuantityPricingRule(new QuantityPricingRule("A", 50));
            pe.AddQuantityPricingRule(new QuantityPricingRule("B", 30));
            pe.AddQuantityPricingRule(new QuantityPricingRule("D", 15));
            pe.AddQuantityPricingRule(new QuantityPricingRule("A", 3, 130));
            pe.AddQuantityPricingRule(new QuantityPricingRule("B", 2, 45));

            ICheckout co = new Checkout(pe);

            co.Scan("A");
            co.Scan("A");
            co.Scan("A");
            co.Scan("B");
            co.Scan("B");
            co.Scan("D");

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 190;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_Undo_Scan_Minus_2A_Then_Exception_Is_Thrown()
        {
            // for undo scan, use positive value for count and set parameter undoScan to true
            IPricingEngine pe = new PricingEngine(
                new List<IPricingRule> {
                    new QuantityPricingRule("A", 1, 50),
                    new QuantityPricingRule("A", 2, 90),
                });

            ICheckout co = new Checkout(pe);

            co.Scan("A", -2, true);

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 90;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_Scan_Nothing_Then_Price_is_0()
        {
            ICheckout co = new Checkout(new PricingEngine());

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 0;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_Scan_CDBA_Then_Price_is_115()
        {
            IPricingEngine pe = new PricingEngine();
            pe.AddQuantityPricingRule(new QuantityPricingRule("A", 50));
            pe.AddQuantityPricingRule(new QuantityPricingRule("B", 30));
            pe.AddQuantityPricingRule(new QuantityPricingRule("C", 20));
            pe.AddQuantityPricingRule(new QuantityPricingRule("D", 15));

            ICheckout co = new Checkout(pe);
            co.Scan("C");
            co.Scan("D");
            co.Scan("B");
            co.Scan("A");
            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 115;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_Scan_A_Then_Price_is_50()
        {
            ICheckout co = new Checkout(new PricingEngine());
            co.GetPricingEngine().AddQuantityPricingRule(new QuantityPricingRule("A", 50));

            co.Scan("A");
            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 50;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_Scan_AB_Then_Price_is_80()
        {
            IPricingEngine pe = new PricingEngine(
                new List<IPricingRule> {
                    new QuantityPricingRule("A", 50),
                    new QuantityPricingRule("B", 30)
                });
            ICheckout co = new Checkout(pe);
            co.Scan("A");
            co.Scan("B");
            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 80;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_Scan_0A_Then_Exception_Is_Thrown()
        {
            IPricingEngine pe = new PricingEngine(
                new List<IPricingRule> {
                    new QuantityPricingRule("A", 1, 50),
                    new QuantityPricingRule("A", 2, 90),
                });

            ICheckout co = new Checkout(pe);

            co.Scan("A", 0);

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 90;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_Scan_3A_At_a_Time_And_Then_Undo_Scan_2A_Then_Price_is_50()
        {
            IPricingEngine pe = new PricingEngine(
                new List<IPricingRule> {
                    new QuantityPricingRule("A", 1, 50),
                    new QuantityPricingRule("A", 2, 90),
                });

            ICheckout co = new Checkout(pe);

            co.Scan("A", 3);
            co.Scan("A", 2, true);

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 50;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_QuantityPricingRule_A_50_And_Scan_AA_Then_Price_is_100()
        {
            IPricingEngine pe = new PricingEngine();
            pe.AddQuantityPricingRule(new QuantityPricingRule("A", 50));
            pe.AddQuantityPricingRule(new QuantityPricingRule("B", 30));

            ICheckout co = new Checkout(pe);

            co.Scan("A");
            co.Scan("A");

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 100;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_QuantityPricingRule_A_50_And_MultiPriceRule_A_3_130_And_Scan_AAA_Then_Price_is_130()
        {
            IPricingEngine pe = new PricingEngine(
                new List<IPricingRule> {
                    new QuantityPricingRule("A", 3, 130),
                    new QuantityPricingRule("A", 50)
                    }
                );
            ICheckout co = new Checkout(pe);
            co.Scan("A");
            co.Scan("A");
            co.Scan("A");

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 130;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_QuantityDiscountPricingRule_A_5_4_And_A_3_2_And_Scan_5A_Then_Price_is_180()
        {
            IPricingEngine pe = new PricingEngine(
                new List<IPricingRule> {
                    new QuantityDiscountPricingRule("A", 3, 2),
                    new QuantityPricingRule("A", 3, 130),
                    new QuantityPricingRule("A", 2, 90),
                    new QuantityPricingRule("A", 1, 50),
                    new QuantityDiscountPricingRule("A", 5, 4),
                });

            ICheckout co = new Checkout(pe);

            for (int i = 0; i < 5; i++)
            {
                co.Scan("A");
            }

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 180;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_QuantityDiscountPricingRule_A_3_2_And_Scan_3A_Then_Price_is_90()
        {
            IPricingEngine pe = new PricingEngine();
            pe.AddQuantityDiscountPricingRule(new QuantityDiscountPricingRule("A", 3, 2));
            pe.AddQuantityPricingRule(new QuantityPricingRule("A", 3, 130));
            pe.AddQuantityPricingRule(new QuantityPricingRule("A", 2, 90));
            pe.AddQuantityPricingRule(new QuantityPricingRule("A", 1, 50));

            ICheckout co = new Checkout(pe);

            for (int i = 0; i < 3; i++)
            {
                co.Scan("A");
            }

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 90;

            Assert.AreEqual(expectedPrice, price);
        }
        public void If_PriceCombination_And_Scan_Random_9A7B_Then_Price_is_530()
        {
            IPricingEngine pe = new PricingEngine(
                new List<IPricingRule> {
                    new QuantityPricingRule("A", 50),
                    new QuantityPricingRule("A", 3, 130),
                    new QuantityPricingRule("A", 5, 190),
                    new QuantityPricingRule("B", 30),
                    new QuantityPricingRule("B", 2, 45),
                    new QuantityPricingRule("B", 4, 85)
                });

            ICheckout co = new Checkout(pe);

            for (int i = 0; i < 7; i++)
            {
                co.Scan("A");
                co.Scan("B");
            }
            for (int i = 0; i < 2; i++)
            {
                co.Scan("A");
            }

            decimal price = co.GetTotalPrice();
            decimal expectedPrice = 530;

            Assert.AreEqual(expectedPrice, price);
        }