Predator II: Just Die Already!

What do they do in in Hollywood if a movie does well at the box office? Make a sequel and use the success of the first movie to milk consumers for more money. Predator did well, earning almost $100M so naturally, Predator II came along three years later. Sequels usually have a common relationship with the original. In the first movie, the hero, after great struggle, finally kills the villain and then the sequel comes along and somehow the villain is back to life causing even more havoc. I see that and get to thinking, "Gosh darn! Why won't that thing JUST DIE ALREADY!?" I ask that question about software defects often because often times, defects have sequels too (and so should blogs)!

Despite my best efforts - thorough coverage, testing every test case I can think of, making sure everything WORKS - out of nowhere pops up some bug that I thought was squashed weeks ago! Sometimes it doesn't matter how big your muscles are, how many bullets you have in your gun, or how many other people have their guns pointed at the same monster, they still come back to life.

This can be caused by any number of things. It could be laziness on the part of the tester (or the developer) but I don't think that's usually the case. Here are some other causes:

1. Unclear requirements
2. Inexperience
3. Lack of time
4. Introduction of new/altered code
5. Using [testing] the software in a way that it wasn't previously used

That last one is a big ball of mud - "WHY DIDN'T YOU TEST IT THAT WAY BEFORE???" See causes 1-4. The truth is, software is extremely complex and it's impossible to account for every scenario. As a tester, you must know how to prioritize and how to look for the scenarios that are most likely to occur and those which have the gravest consequences because there just isn't time/budget/people-power to do it all.

When defects do reoccur, use it as a learning catalyst. Was there an obvious breakdown in the development or testing methodology? Is this a "new" method of execution that should be noted for the future and with application other scenarios? Is there a different testing technique or tool that might have been able to expose that the defect was not fully resolved earlier?

Old defects will continue to pop up. Don't be discouraged but remain vigilant. Keep sharpening your skills and be ready for the enemy to return, because he always does, sometimes with Aliens.