In search of the potato… Rikard Edgren
When preparing for EuroSTAR 2009 presentation I drew a picture to try to explain that you need to test a lot more than the requirements, but we don’t have to (and can’t) test everything and the qualitative dilemma is to look for and find the important bugs in the product.
Per K. instantly commented that it looked like a potato, judge for yourself:
The square symbolizes the features and bugs you will find with test cases stemming from requirements (that can’t and shouldn’t be complete.)
The blue area is all bugs, including things that maybe no customers would consider annoying.
The brown area is all important bugs, those bugs you’d want to find and fix.
So how do you go from the requirements to “all important bugs”?
You won’t have time to create test scripts for “everything”.
So maybe you do exploratory testing (thin lines in many directions), and hope for the best.
Or maybe you test around one-liners (thicker horizontal lines), that are more distinct, that are reviewed, and have a better chance of finding what’s important.
Either option, some part luck, and a large portion of hard work is needed.
But I think you have a much better chance if you are using one-liners, especially if it’s a larger project.
Later I have realized that one-liners aren’t essential; that this problem has been solved many times at many places with many different approaches.
What is common could be that testers learn a lot of things from many different sources, combine things, think critically and design tests (in advance or on-the-fly) that will cover the important areas.
Maybe we need a name for this method; it could be Grounded Test Design.