Someone on the agile-testing Yahoogroup mailing list posted a link to a blog post in which he proceeded to misuse, maul and maim the Agile Testing Quadrants. There is no way to put comments on that blog post to try to refute his claim that the quadrants are somehow a waterfall process. Since other people might misunderstand the purpose of the quadrants, I’d like to put a quick explanation here.
The quadrant numbering system does NOT imply any order. You don’t work through the quadrants from 1 to 4, in a waterfall style. It’s just an arbitrary numbering so that, in our book and when we are talking about the quadrants, we can say “Q1″ instead of “technology-facing tests that support the team”.
Most projects would start with Q2 tests, because those are where you get the examples that turn into specifications and tests that drive coding, along with prototypes and the like. However, I have worked on projects where we started out with performance testing (which is in Q4) on a spike of the architecture, because that was the most important criterion for the feature. If your customers are uncertain about their requirements, you might even do a spike and start with exploratory testing (Q3).
Q3 and Q4 testing pretty much require that some code be written and deployable, but most teams iterate through the quadrants rapidly, working in small increments. Write a test for some small chunk of a feature, write the code, once the test is passing, perhaps automate more tests for it, do exploratory testing on it, do security or load testing on it, whatever, then add the next small chunk and go through the whole process again.
The quadrants are merely a taxonomy to help teams plan their testing and make sure they have all the resources they need to accomplish it. There are no hard and fast rules about what goes in what quadrant. Think through them as you do your release, theme, and iteration planning, so your whole team starts out by thinking about testing first.
Visit my Presentations page for some slide decks that contain more information on the quadrants, or check out our book. I’m always happy to talk about the quadrants, just send me an email!