public void Initialize()
        {
            ItemManager.InitializeInventory();

            dexterityVest    = new DexterityVest("+5 Dexterity Vest", 10, 20);
            agedBri          = new AgedBrie("Aged Brie", 2, 0);
            elixirOfMongoose = new MongooseElixir("Elixir of the Mongoose", 5, 7);
            handOfRagnaros   = new Sulfuras("Sulfuras, Hand of Ragnaros", 0, 80);
            backstagePass    = new BackstagePass("Backstage passes to a TAFKAL80ETC concert", 15, 20);
            manaCake         = new ManaCake("Conjured Mana Cake", 3, 6);
        }
        public void SingleRunOfUpdateQuantity()
        {
            ItemManager.UpdateQuality();

            dexterityVest    = new DexterityVest("+5 Dexterity Vest", 9, 19);
            agedBri          = new AgedBrie("Aged Brie", 1, 1);
            elixirOfMongoose = new MongooseElixir("Elixir of the Mongoose", 4, 6);
            handOfRagnaros   = new Sulfuras("Sulfuras, Hand of Ragnaros", 0, 80);
            backstagePass    = new BackstagePass("Backstage passes to a TAFKAL80ETC concert", 14, 21);
            manaCake         = new ManaCake("Conjured Mana Cake", 2, 5);

            Assert.AreEqual(6, ItemManager.Items.Count());
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(dexterityVest)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(agedBri)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(elixirOfMongoose)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(handOfRagnaros)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(backstagePass)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(manaCake)));
        }
        public void ThreeRunsOfUpdateQuantity()
        {
            ItemManager.InitializeInventory();
            updateQuantityNTimes(3);

            dexterityVest    = new DexterityVest("+5 Dexterity Vest", 7, 17);
            agedBri          = new AgedBrie("Aged Brie", -1, 4);
            elixirOfMongoose = new MongooseElixir("Elixir of the Mongoose", 2, 4);
            handOfRagnaros   = new Sulfuras("Sulfuras, Hand of Ragnaros", 0, 80);
            backstagePass    = new BackstagePass("Backstage passes to a TAFKAL80ETC concert", 12, 23);
            manaCake         = new ManaCake("Conjured Mana Cake", 0, 3);

            Assert.AreEqual(6, ItemManager.Items.Count());
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(dexterityVest)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(agedBri)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(elixirOfMongoose)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(handOfRagnaros)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(backstagePass)));
            Assert.IsNotNull(ItemManager.Items.FirstOrDefault(i => i.Equals(manaCake)));
        }