This is similar to how the system at Oxford works (I think this is how the rest of the British universities do it as well.). Your degree class (essentially your GPA) is solely based on tests you take at the end of every year of your degree (three for a BA, four for a MComp). There are practicals (lab sessions) and tutorials (conversations with tutors about problem sets), but those don't affect your degree class, unless you do terribly.

With all the testing in American universities, the British (?) system is quite refreshing.