public void CreateAndOutput(string name, string contactphone, decimal revenue)
        {
            var a = new OutputCustomerData(name, revenue, contactphone);

            Assert.AreEqual(name, a.Name);
            Assert.AreEqual(revenue, a.Revenue);
            Assert.AreEqual(contactphone, a.ContactPhone);
        }
        public void TestToString(string name, string contactphone, decimal revenue, string fmt, string result)
        {
            var a = new OutputCustomerData(name, revenue, contactphone);

            Assert.AreEqual(a.ToString(fmt), result);
        }