There's more to BDD than evolving TDD

Behaviour-driven development started life as an NLP exercise to stem the abuse of the word “test” in “test-driven development”. Since then it has grown into a respectable and proven agile methodology (with a small “m” of course).

Dave Astels, the award-winning author, was an early adopter of BDD and has been instrumental in raising its profile. He presented it at Canada on Rails and is taking it to JAOO and SD Best Practices. He has even presented it to Google. His Ruby BDD framework, rspec, has inspired a number of similar projects.

Now, Dave is a programmer. What’s more, he is a very thoughtful programmer, which means he invests a lot of energy in making programming productive and effective — and more importantly fun — for himself and other programmers. He doesn’t get very excited about capturing requirements or the dynamic between testers and analysts, so you won’t hear him talking about the wider context of BDD, but you will hear him saying that there is one!

BDD is fundamentally about identifying behaviour. At the analysis level, the behaviour of a story is its acceptance criteria, which BDD expresses in the form of automated scenarios. You need analysts working with testers to capture the stories and identify the acceptance criteria, and then you need programmers working with testers to automate the scenarios.

So the ironic twist is that all that talk about “testing” in TDD was taking the focus off the real testing action! My efforts to put the word “test” back in its box have in fact propelled the testers into the central role on a BDD team.

So the message here is twofold. Firstly, although a lot of the existing BDD message is in the TDD space, don’t lose sight of the bigger picture or you’ll miss out on all the good stuff. And secondly don’t underestimate the value of the testers on your team: they are your direct line to delivering high value software.