So what happened? Well, we hit our ruts again.
Humans are predisposed to inattentional blindness, and this can easily kill testing. Something is wrong, and you just don't see it. This becomes worse when you're looking at the same things every day - and this happens to al of us. There's "the guy who knows the upgrader" and he tests the upgrader in every release, etc.
So how do we break out of our ruts? How do we reduce inattentional blindness?
- Switch it up. Every so often - at least once a week or so - switch to looking at a component you haven't looked at in a while.
- Play Games. This one can be effective when you are in a test case rut. Think soap opera tests, or headline tests. Anything that is not normally how you develop test cases.
- Go away for a while. Stop testing for a bit. Go work on something else - that new script you needed, defect aging analysis, whatever.
- Don't forget the 12 hour rule. After 12 hours, I don't trust your results any more. Your error rate will go through the roof. This goes for everyone, not just testers.