public void Divide(double a, double b)
        {
            double       x = a, y = b;
            MyCalculator my = new MyCalculator();

            Assert.AreEqual(x / y, my.division(x, y));
        }
        public void Subtract(double a, double b)
        {
            double       x = a, y = b;
            MyCalculator my = new MyCalculator();

            Assert.AreEqual(x - y, my.Subtract(x, y));
        }
        public void Multiply(double a, double b)
        {
            double       x = a, y = b;
            MyCalculator my = new MyCalculator();

            Assert.AreEqual(x * y, my.multiply(x, y));
        }
        public void Add(double a, double b)
        {
            double       x = a, y = b;
            MyCalculator my = new MyCalculator();

            Assert.AreEqual(x + y, my.Add(x, y));
        }