Structuring Groovy tests

Hi-

I've just started using Webtest following a pure groovy approach as
described here:
http://mguillem.wordpress.com/2009/04/30/webtest-with-groovy-maven-and-eclipse/

Now I'm wondering what's the best way to structure the tests.
Many tests will make use of common steps, like logging into the website,
putting a product into a shopping cart, etc.)
So what I'm trying to achieve is being able to write tests like this:

        webtest('My Test') {

            addToCart(ean: 12345567)

            login(user: user, password: pasword)

            // some 'regular' webtest calls
        }

Is anyone using webtest with groovy in a similar fashion? Also does anyone
have pointers to non trivial examples of groovy webtests?

Thanks for your help,

-markus