public void Step3()
        {
            CalculatorKata calculatorKata = new CalculatorKata();

            Assert.AreEqual(calculatorKata.Add("1,3"), 4);
        }
        public void Step4()
        {
            CalculatorKata calculatorKata = new CalculatorKata();

            Assert.AreEqual(calculatorKata.Add("3,-5,3,9"), 15);
        }
        public void Step2()
        {
            CalculatorKata calculatorKata = new CalculatorKata();

            Assert.AreEqual(calculatorKata.Add("0"), 0);
        }