Adam @ Bitscribe

Behavior-Driven Development (BDD) has been hanging around, tugging gently at my brain for a few months now. Like most interesting ideas, it’s only a small evolutionary step from its predecessor, TDD. But I think it’s a subtly powerful concept, one that I’m starting to pay more and more attention to in my work. The introduction sums up the evolutionary shift at a personal level:

1. The developer starts writing unit tests around their code using a test framework like JUnit.
2. As the body of tests increases the developer begins to enjoy a strongly increased sense of confidence in their work.
3. At some point the developer has the insight (or are shown) that writing the tests before writing the code, helps them focus on only writing the code that they need.
4. The developer also notices that when they return to some code that they haven’t seen for a while, the tests serve to document how the code works.
5. A point of revelation occurs when the developer realises that writing tests in this way helps them to “discover” the API to their code. TDD has now become a design process.
6. Expertise in TDD begins to dawn at the point where the developer realizes that TDD is not about testing, it is about defining behaviour.
7. Behaviour is about the interactions between components of the system and so the use of mocking is a fundamental to advanced TDD.

Word.

This entry was posted on Friday, March 2nd, 2007 at 12:22 am and is filed under Design, TDD. You can follow any responses to this entry through the RSS 2.0 feed. Responses are currently closed, but you can trackback from your own site.