public void FactorialApprovalTests()
        {
            StringBuilder fakeoutput = new StringBuilder();

            Console.SetOut(new StringWriter(fakeoutput));
            Console.SetIn(new StringReader("a\n"));

            Console.WriteLine("1 -> " + Factorial.calculate(1));
            Console.WriteLine("2 -> " + Factorial.calculate(2));
            Console.WriteLine("3 -> " + Factorial.calculate(3));
            Console.WriteLine("10 -> " + Factorial.calculate(10));
            string output = fakeoutput.ToString();

            Approvals.Verify(output);
        }