public void DropShoppingCart_Should_ZeroOutCart_RestoreInventory()
{
var store = new OnlineStore(new Catalog());
var customerName = CustomerName;
store.CreateShoppingCart(customerName);
var originalTotalInventory = Catalog.GetTotalProducts();
store.AddItemToShoppingCart(customerName, ProductTypeEnum.Tent, 3);
Assert.AreEqual(originalTotalInventory - 3, Catalog.GetTotalProducts());
store.AddItemToShoppingCart(customerName, ProductTypeEnum.Backpack, 2);
Assert.AreEqual(originalTotalInventory - 3 - 2, Catalog.GetTotalProducts());
Assert.AreEqual(3, store.GetItemCountInCart(customerName, ProductTypeEnum.Tent));
Assert.AreEqual(2, store.GetItemCountInCart(customerName, ProductTypeEnum.Backpack));
store.DropShoppingCart(customerName);
Assert.AreEqual(store.GetItemCountInCart(customerName, ProductTypeEnum.Tent), 0);
Assert.AreEqual(store.GetItemCountInCart(customerName, ProductTypeEnum.Backpack), 0);
// total inventory changed back
Assert.AreEqual(originalTotalInventory, Catalog.GetTotalProducts());
}