In this example, we'll ask you to build a ShoppingCart class which contains multiple items, and provides a method of adding, removing and updating items belonging to a cart. The ShoppingCart class is a plain Ruby class, which should only use objects which belong to the standard Ruby library.
First, fork this example. Click 'Fork' above. Then, you'll clone, edit, add, commit and push your changes as necessary. Notify us with a link to your forked example when you're finished.
Please first develop tests (either using TDD or BDD libraries of your choice -- we like Test::Unit and RSpec, but you're free to use whatever method you're comfortable with) before you write actual code. We're a test-driven shop.