Testability and Design

As Michael Feathers notes, 'The Deep Synergy Between Testability and Good Design', there is a lot of discussion about how to test private methods. I think he's absolutely correct that the need to test a private method is a hint about the design. I've been reviewing a class that I was never completely happy with because it exposes private methods for testing. Looking at it today I'm sure it would be possible to extract a class that would improve the design and fix the problem. It would have been much easier to clean this up when I was writing the code than to find the time to fix it now. I wish I had listened closer to the hint that my test was giving me.

It's pretty amazing how much we learn about the goodness of a design when try to test it. In the past I used to write fewer and larger classes than I do today. Most of the reason for the change is for better unit tests.

The Discipline of Agile

An article by Scott Ambler at Dr. Dobb's does a nice job refuting the idea that agile development is not disciplined. I think some of this might come from the lack of ceremony on agile development projects. Things get done and no one makes a big deal of it. Software is normally usable (and very likely releasable) at the end of every iteration, so the actual release can be anti-climatic. Contrast that with traditional methods where every phase or milestone is a big deal and release is often an earth shaking event. Maybe the traditionalists are just mistaking all their ceremony for real discipline.