public void Test_Constructor_RetrieveStock()
{
//Arange
var imi = new InMemoryInventory();
//assert constructor works
Assert.IsNotNull(imi);
Assert.IsNotNull(imi.Items);
//assert the item count in inventory is greater than zero
Assert.IsTrue(imi.Items.Any());
}
public void Test_Buy_An_Item_Until_The_Stock_IsEmpty()
{
var imi = new InMemoryInventory();
var firstLowStockItem = imi.Items.OrderBy(itm => itm.Quantity).FirstOrDefault();
Assert.IsNotNull(firstLowStockItem);
var initialQuanity = firstLowStockItem.Quantity;
Item item;
//iterate the BuyItem method until the stock is depleted
for (var i = 0; i < initialQuanity; i++)
{
//assert the purchase succeeds
Assert.IsTrue(imi.BuyItem(firstLowStockItem.Id, out item));
}
//assert that attempting to buy an item when stock depleted is not possible
Assert.IsFalse(imi.BuyItem(firstLowStockItem.Id, out item));
}
public void Test_AsyncCallForBuyMethodRespectsInventoryCount()
{
var imi = new InMemoryInventory();
//sample an item with a large amount of inventory stock;
//capped to 20 as we will spawn a thread count based on this number
var mostNumerousStockItem = imi.Items.Where(itm => itm.Quantity < 20).OrderByDescending(itm => itm.Quantity).FirstOrDefault();
Assert.IsNotNull(mostNumerousStockItem);
Item item;
var initialQuantity = mostNumerousStockItem.Quantity;
var tasks = new List <Task <bool> >();
//spawn double the quantity amount of threads to insure some threads will attempt to buy after the stock depleted
for (int i = 0; i < 2 * initialQuantity; i++)
{
tasks.Add(Task.Run(() => imi.BuyItem(mostNumerousStockItem.Id, out item)));
}
Task.WhenAll(tasks).Wait();
//assert that the amount of bought items matches the inventory count
Assert.AreEqual(initialQuantity, tasks.Count(t => t.Result));
}
