public void TestMultiplyAll()
        {
            IFancyCalculator x = new FancyCalculator();

            x.Push(10);
            x.Push(10);
            x.Push(10);
            x.Push(10);
            Assert.IsTrue(x.Top() == 10);
            x.MultiplyAll();
            Assert.IsTrue(x.Top() == 10000);
        }