One of the goals of Spring MVC has always been to allow you to test your controllers right inside your IDE, without having to fire up your web app in a servlet engine. It's always gratifying during trainings to see the faces of old-time Struts developers light up as they see just how easy this is to achieve. Here are a couple of blog entries I came across recently which give a glimpse into the Spring MVC testing experience:

Craig Walls: Unit-testing Spring MVC: It gets even awesomer

John Ferguson Smart: Unit testing your Spring-MVC applications