public void TestDecorators()
{
Order o = new PhotoCamera();
o = new Lens(o);
Assert.AreEqual(o.cost(), 1799);
o = new Filter(o);
Assert.AreEqual(o.cost(), 1822.50);
o = new Extender(o);
Assert.AreEqual(o.cost(), 2251.50);
Order order = new VideoCamera();
order = new Lens(order);
Assert.AreEqual(order.cost(), 2299);
order = new Filter(order);
Assert.AreEqual(order.cost(), 2322.50);
order = new Extender(order);
Assert.AreEqual(order.cost(), 2751.50);
}
