public int TestSubtraction(int x, int y, int result)
        {
            var calc = new calculatorLibrary.Calculator();

            return(calc.Subtract(x, y));
        }
        public void TestAddition(int x, int y, int result)
        {
            var calc = new calculatorLibrary.Calculator();

            Assert.Equal(result, calc.Add(x, y));
        }