I failed! Yes I did and I'm not ashamed about it either. I learned an important lesson and I thought I’d share it.
As I have mentioned before on this blog I am involved in both testing and in developing a PDM system with a large number of users and it was in this system I failed to find a pretty nasty bug.
The bug had been in production for some time and no one had reported any problems. Now we were putting in new functionality that opened this Pandora’s Box. The bug was particularly nasty because as a user you would get no feedback from the system at all even if you fell victim to it. This is an extremely nasty class of bugs. The bugs that will mess up data and you have no idea.
So what was it? What did this nasty bug do? It changed data in the background, underneath an edit form, causing you to believe you were changing metadata for one object when in fact you could be changing the same metadata for a different object. The metadata not being displayed in the standard presentation of the objects you could do this without seeing it. The only way you’d know something was wrong was if you looked for the change you thought you made and discovered it wasn’t there. You might guess that you closed the editing form without committing the change or that possibly the system failed to commit the data. I don’t think that a lot of people, even testers, would think that perhaps they changed the data for some other object. If your testing a brand new system you would look for things of that nature but in a system that has been live in production for years and has been evolving over those years you would, at least I would and did, assume that there’s no way a bug of that kind could have slipped through. That was one of my mistakes! Don’t make assumptions without testing them . I know this, and I’m sure you do to, but the human mind being what it is, we assume things. We take things for granted and we are biased. Might as well admit it. It’s true.
We found it, or a colleague of mine found it, and there was much rejoicing. Well, that’s not the counting the poor guy who had to fix it quickly since we were in the middle of putting a new release in place in the production environment. He did pull of a good enough fix.
All is well that ends well and the good enough fix will be made better and eventually launched into the production environment in June. I learned a few things and that is always good. Don’t make assumptions without testing them, test all around and question yourself if you don’t find any bugs. Test all around is my key to remember to test clicking on stuff outside the form/dialog/div that I’m currently in and also to looking for interactions between the surrounding context of a form/dialog/div that might not be obvious or even readily visible.
Think for yourselves. I try to!