public void addGuestTest2()
        {
            OrderServer.addGuest("", "", "", 0);
            List <Order> Inf2 = new List <Order>()
            {
                new Order("001", "A", "a", 11000),
                new Order("002", "B", "b", 9000),
                new Order("003", "C", "c", 15000),
                new Order("", "", "", 0)
            };

            Assert.AreEqual(Inf2, Inf2);
        }