Testing WO code

I'm still looking at WO/Wonder versus Spring/Hibernate/Tapestry.

One of the benefits of using Spring is that you can separate dependent 
layers, and use IOC/dependancy injection (with configuration) to make 
them work together. This lets you better isolate the different layers 
of an application, which has the side effect of making testing much 
easier. (You can build your model classes entirely of POJOS and POJIs, 
for example.)

So how does this play out in WO? How difficult is it to build an 
automated testing process for WebObjects (for example)? Am I missing 
some critical point in the development process? Is there a WO project 
available that helps one test their WO code?

Doug