This days, along with the great progress of modern browsers (well OK, expect IE) and the evolvement of the web, many responsibilities within our software that once was integral part of our server, moved in to the front end and made front end apps deal with large code bases and heavy controller logics that eventually gave us the freedom and ability to create kick-ass web applications.
It caused some brilliant people around the world to come out with great frameworks that allow FEDs to focus on business logics and avoid lots of boilerplate code.
Writing testable code, makes our code decoupled, independent and extendable; It provides us to easily test and refactor our code which makes maintenance a much easier task which is essential to any product.
Here is the presentation:
Although my lecture was is in hebrew, here is a link to whoever is interested.