It's a very interesting article that promotes delegation of object life-cycle management. Right now, in my project we are implementing some agile methodologies that includes TDD. [It's an spring + hibernate app]
I think mock objects for testing isolated layers would be useful, the only tradeoff that I see is the use of MockObjectTestCase class through inheritance.
I think we will follow a more decoupled approach, fortunately in the
jmock's geeting started site, there are plenty of examples to accomplish this by favoring composition [desing principle: favor composition over inheritance] or even by using annotations.
[ April 14, 2008: Message edited by: Omar Palomino Sandoval ]