public void TestAdd()
        {
            var sc = new stubCalculator();

            Assert.AreEqual(4, sc.Add(2));
            Assert.AreEqual(9, sc.Add(3));
        }
        public void TestAdd()
        {
            var sc = new stubCalculator();
            var sb = new Production.SchoolBag(sc);

            Assert.AreEqual(4, sb.Add(2));
            Assert.AreEqual(9, sb.Add(3));
        }