Books I mentioned
In my XP/Agile Universe keynote, I cited a bunch of books. Someone asked that I post them, so here they are.
One bit of evidence that test-driven design has crossed the chasm and is now an early-mainstream technique is JUnit Recipes, by J.B. Rainsberger. This is a second-generation book, one where he doesn't feel the need to sell test-driven design. He's content (mostly) to assume it.
I asked how it could be that Agile projects proceed "depth-first", story-by-relatively-disconnected-story, and still achieve what seems to be a unified, coherent whole from the perspective of both the users and programmers. My answer was the use of a whole slew of techniques.
At the very small, programmers are guided by simple rules like Don't Repeat Yourself. Ron Jeffries' Adventures in C# is a good example of following such rules. Martin Fowler's Refactoring is the reference work for ways to follow those rules.
At the somewhat higher level, we find certain common program structures: patterns, as described in Design Patterns. Joshua Kerievsky's new Refactoring to Patterns shows how patterns can be the targets of refactoring. You can think of patterns as "attractors" of code changes.
I was resolutely noncommittal about whether the larger-scale patterns can emerge from lower-level refactorings or whether pre-planning is needed. I tossed in Hunt and Thomas's The Pragmatic Programmer both because it (and they) speak to this issue and because it seems to fit somehow in the "architectural" space.
Finally, I addressed an issue that's been weighing on my mind for more than a year. Dick Gabriel has said (somewhere that I can't track down precisely) that there are two approaches to quality. The one approach is that you achieve quality by pointing out weaknesses and having them removed. The other is that you build up all parts of the work, including especially (because it's so easy to overlook) strengthening the strengths.
Testers too often take the first approach as a given. They issue bug reports, become knowledgeable discussants about the weaknesses of the product, and think they've done their job. And they're right, on a conventional project. I've decided I don't want that to be their job on an Agile project; instead, I want them to follow the second approach. I want them to apply critical thinking skills to the defense and nurturing of a growing product.
But what could that mean? How can it be done? I proposed mining the knowledge of other skilled laborers for ideas. Latour and Woolgar's Laboratory Life: the Construction of Scientific Facts describes how teams of scientists collaborate to produce their primary work product: published and widely-cited scientific papers. (I've written about that earlier.)
I mentioned another source: writers' workshops as used in the creative writing community and imported into the patterns community. Richard P. Gabriel's Writers' Workshops and the Work of Making Things is the reference work here. (See also James Coplien's online "A Pattern Language for Writers' Workshops".