If you show a model (with a lot of attributes) partially in a CGridView, it can be helpful when the user can take a quick look at the full record with all attributes without displaying the view
as a page and afterwards returning back to the gridview.
Unfortunately Sebastian Bergmann decided to remove PHPUnit_Story from future PHPUnit versions. Thanks to elvan for pointing me to the relevant comment. As an alternative Behat has been suggested but it seems too bloated for me TBH. There is also PHPSpec but it's non flexible enough for me and tightly bound with English language (What's the purpose of using DSL if customers can't speak English). Since both frameworks are quite young I think I'll just stick to PHPUnit and see what's going on on the BDD frameworks arena. Even PHPUnit_Story parts of this entry are going to be deprecated soon, rest is still valid! When doing TDD, please write tests with design and behaviour of application in mind instead of testing single functions.
There are some good guides out there explaining how to work with events and the ways to attach them to your components, but none (that I know) explain the following way to configure your events with CAction classes on your controllers the following way.