public void Faliure(string name, int age, string number, string brand, int plan, bool more3GB, bool unlimitedCall)
        {
            testUser = new user(name, age, number, brand);
            PlanSelector selector = new PlanSelector(testUser);

            Assert.IsFalse(selector.ChangePlan(plan, unlimitedCall, more3GB));
            Assert.AreEqual(0, testUser.CurrentPlan);
        }
        public void expectException(string name, int age, string number, string brand, int plan, bool more3GB, bool unlimitedCall)
        {
            try
            {
                testUser = new user(name, age, number, brand);
                PlanSelector selector = new PlanSelector(testUser);
                Assert.IsTrue(selector.ChangePlan(plan, unlimitedCall, more3GB));
                Assert.AreEqual(plan, testUser.CurrentPlan);
            }

            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }