public void TestShouldStillPriceMultiBuyDeal()
        {
            var testObj = new BuyXGetXFreeDeal('A', 2, 1);

            var testData = "AAA".ToCharArray();

            var result = testObj.Apply(testData);

            Assert.AreEqual(100, result.Item2);
        }
        public void TestShouldRemoveAllObjects()
        {
            var testObj = new BuyXGetXFreeDeal('A', 2, 1);

            var testData = "AAA".ToCharArray();

            var result = testObj.Apply(testData);

            Assert.AreEqual(0, result.Item1.Length);
        }