public void AddLeafItemSucceeds()
        {
            IInventoryItem backpack = new InventoryContainer("Backpack", 100);
            IInventoryItem sword    = new Sword("Masamune", 50);

            backpack.AddItem(sword);

            Assert.IsTrue(backpack.Contains(sword));
        }
        public void AddCompositeItemSucceeds()
        {
            IInventoryItem backpack = new InventoryContainer("Backpack", 100);

            IInventoryItem spellBook = new UniqueInventoryContainer("Spellbook", 100);

            backpack.AddItem(spellBook);

            IInventoryItem fireball = new Spell("Fireball", 100);

            spellBook.AddItem(fireball);

            Assert.IsTrue(backpack.Contains(spellBook));
            Assert.IsTrue(spellBook.Contains(fireball));
        }