public void AddOrReplaceTest()
{
ItemList list = new ItemList();
Item stackableItem = TestUtils.RandomStackableItem();
Item nonStackableItem = TestUtils.RandomNonStackableItem();
int count = stackableItem.Count;
Item junkedItem = list.AddOrReplace(stackableItem);
Assert.AreEqual(1, list.Count);
Assert.IsNull(junkedItem);
Assert.AreEqual(count, list.CountOf(stackableItem.ItemType));
junkedItem = list.AddOrReplace(stackableItem);
Assert.AreEqual(1, list.Count);
Assert.IsNull(junkedItem);
Assert.AreEqual(count * 2, list.CountOf(stackableItem.ItemType));
junkedItem = list.AddOrReplace(nonStackableItem);
Assert.AreEqual(2, list.Count);
Assert.IsNull(junkedItem);
Assert.AreEqual(1, list.CountOf(nonStackableItem.ItemType));
junkedItem = list.AddOrReplace(nonStackableItem);
Assert.AreEqual(2, list.Count);
Assert.AreEqual(nonStackableItem, junkedItem);
Assert.AreEqual(1, list.CountOf(nonStackableItem.ItemType));
// TODO: Test a non-stackable item replacing an inferior item
}