You’re a discerning, thorough, and creative software tester, right? You bet! So how is it that bugs still manage to make it to production?Here are 4 reasons why a bug may be missed – and what you can do about it:


1. Testing didn’t hit the right combination of factors to trigger it.

Sometimes triggering a bug takes the perfect storm of the right (or wrong?) web browser, browser version, OS, screen dimensions, device…Because testing can never cover everything, it’s possible that you’ll never hit that specific bug-triggering combination. When that happens, a bug may slip through to production and stay hidden until a user discovers it “in the wild.”

What you can do about it: Whenever possible and practical, test your application under several different combinations of conditions. Pay particular attention to the combination most commonly used by your customers.


2. It’s been there for a long time and has been forgotten.

Ah, the backlog! It’s supposed to allow us to keep track of all of the bug fix tickets so we can prioritize them and work them into the sprint or project plan.Although we have good intentions when we create a follow-up issue to resolve a bug, unfortunately sometimes the backlog is like the Island of Misfit Toys. These tickets are created, dropped in the backlog, and forgotten – and thus, their bugs are forgotten too.

What you can do about it: Whether your team is Agile or not-so-Agile, make sure that someone treks through the backlog from time to time to make sure that the bugs filed there aren’t forgotten. You may even discover some that don’t exist anymore and can be closed!


3. Someone noticed it but didn’t speak up.

With the tension between testers and developers that plagues some companies, it’s not always easy to point out a bug. In fact, it can be downright intimidating. This is be even more true when the tester is new to the testing craft or new to the team, or when the developer is a highly respected senior programmer.If a tester notices a bug – or even just a possible bug – and doesn’t mention it, the chances of getting that issue resolved are pretty slim indeed.


What you can do about it: Foster an open, respectful, and approachable team culture. Make sure that all testers, regardless of experience level, know that they don’t need to be afraid to ask questions and point out things that don’t seem quite right.

4. Another bug obscured it.
Few things are as effective at hiding a bug than another bug that prevents you from triggering it or reaching it in the first place.Say you’re testing a new feature. Things seem to be going well, but suddenly you reach a point where further testing isn’t even an option because of a bug. For example, maybe you need to click a link to actually use that new feature, but the link isn’t there at all.You’ll have no way of knowing that there’s a problem with how that new feature works on a mobile device if you can’t even get the new feature to appear.

What you can do about it: Be sure to take thorough testing notes on what you did and didn’t cover in any given round of testing – you’ll help both yourself and the dev. Once that failed ticket is fixed and testable, start from the beginning and test it in full.


Please find the original blog post written by Cullyn Thompson here.