Tuesday, 21 June 2011

Test (Behaviour) Driven Development

Recently I saw a pretty nice post:

"If you see anyone pushing code to Rails without tests, ping me and I will gladly revert. In 2011, this should be unacceptable."

I remember times when I had a project which was developed test driven at my former place of work. Of course the Test Driven initiator was me, and by time the teammates embraced the methodology and it managed to be a very successful project.

The most exciting thing was that I never had to debug; the tests always showed me the exact the location of the problem -if there was any.
Another almost unbelievable fact was that days before releases we didn't have any unfinished tasks. We were down on the streets having a Budweiser or limonade and we were chatting. What I mean here is that the test batteries saved us so much time that we never had to work overtime. We were just shipping the product confidently days before the planned release. I also remember some sales meetings where this project was showed to the customers as a success story. I also remember one of the questions one customer asked: "Then why don't you write software this way every time?" and the answer was "Because some customers simply dictate to not write any test at all..." Well everyone in the meeting laughed. But we all knew that this decision would cause any customer to throw out hundreds of thousand of dollars and hundreds of hours of overtime for the developers without mentioning the moral downgrade for every involved party. Maybe we were laughing at that unintelligent stereotype.
I also remember one important fact while writing this. In the initial project schedule the testing time wasn't calculated. We simply adopted the test first and then the benefits showed themself over and over again. We couldn't run out of the schedule... :) Almost unbelievable but it was true.

After the project has been finished I have tried to introduce this methodology in as many projects as I could. Unfortunately there were some projects where the mass was so frozen that my attempts were totally ignored. Sometimes the reason for ignorance was simply the lack of infrastructure. Fortunately the infrastructure is not a problem in Ruby on Rails. The community is also mostly test-centered.

I cannot emphasize enough for every developer in any domain to embrace this Test First thinking. There are so many benefits of it that many books have been written about it. And who knows, maybe you who will embrace this approach, will have some similar success story to tell the world