public void should_get_orders_of_customer()
        {
            var kent = new Customer("Kent");
            var martin = new Customer("Martin");

            var foodForKent = new Order(kent, "Food");
            var musicForKent = new Order(kent, "Music");
            var foodForMartin = new Order(martin, "Food");

            kent.AddOrder(foodForKent);
            kent.AddOrder(musicForKent);
            martin.AddOrder(foodForMartin);
            var orders = new List<Order> {foodForKent, musicForKent, foodForMartin};
            Assert.Equal(2, GetCustomerOrders(orders, "Kent").Count);
            Assert.Equal(9, kent.GetPriceFor(foodForKent));
        }
 public static void AddCustomer(Customer customer)
 {
     Customers.Add(customer);
 }