Go take a look at the 353 page book, free in pdf format, "FIT for Developing Software: Framework for Integrated Tests" by Rick Mugridge and Ward Cunningham.
"This book is intended to help improve your fitness and agility in two areas of software development where we can make huge improvements to current practice.
First, how to improve communication between the people who need the software and the people who develop it. Second, how to use automated testing to provide immediate and effective feedback so we can maintain balance and agility, and avoid "injury".
The book also questions some common assumptions about the way in which software is developed. But we don’t expect that you’ll make a big leap of faith; we start with current practice and show how you make small, yet effective improvements."
