public void AddItem_Should_Add_A_New_Item_To_List()
{
var itemFixture = _fixture.Create <Item>();
_orderManager.AddItem(itemFixture);
Assert.AreEqual(1, _item.Items.Count);
Assert.AreEqual(itemFixture.ItemNumber, _item.Items[0].ItemNumber);
Assert.AreEqual(itemFixture.AvailableQuantity, _item.Items[0].AvailableQuantity);
Assert.AreEqual(itemFixture.Price, _item.Items[0].Price);
Assert.AreEqual(false, _item.Items[0].IsDealItem);
}