I blinked, and thought about the question because I think it reflects a very deeply-rooted feeling about testing — that testing is somehow secondary to application code; that it’s somehow gravy on top of the real meat.
“I don’t think so,” I answered. “I think that recognizing the constraints imposed by testing are valid influencers of design.”
And the more I thought about it, the more I started to recognize that the ability to test is one of the things that attracts me to systems designed on top of Spring, rather than systems designed on top of EJB. And that makes me feel like the design of Spring is better than the design of EJB.