public void Can_Delete_Book()
        {
            int id = 3;

            Mock <IRepository <Order> > mock = new Mock <IRepository <Order> >();

            mock.Setup(m => m.GetAll()).Returns(new List <Order> {
                new Order {
                    Id = 1, Name = "Order1"
                },
                new Order {
                    Id = 2, Name = "Order2"
                },
                new Order {
                    Id = 3, Name = "Order3"
                },
            });

            //BookRepository repository = new BookRepository();
            TestHelps repository = new TestHelps();

            List <Order> orders = repository.DeleteOrder(mock.Object, id);

            Assert.AreEqual(2, orders.Count);
        }