A nervous tourist, glances back and forth between their phone and the street sign. They then rotate their phone 180 degrees, pauses, blink and frown. The lost traveller, flags a nearby ‘local’ (the passer-by has a dog on a lead. “Excuse me…” she squeaks, “How may I get to Tower Hill?” “Well, that’ s a good one” ponders the dog walker, “You know…” “Yes?” queries the tourist hopefully. “Yeah…” A long pause ensues then, “Well I wouldn’t start from here” He states confidently. The tourist almost visibly deflates and starts looking for an exit. That’s often how we start off in software testing. Despite the flood of methodologies, tips on pairing, power of three-ing, backlog grooming, automating, refining and all the other … ings ) We often find ourselves having to figure out and therefore ‘test’ a piece of software by us ing it. And that’s good. Its powerful, and effective if done right. But, like our dog walker, we can sometimes find ourselves somewhere unfamiliar...
It's an excellent point and a wonderful way of showing it, Pete. A few refinements:
ReplyDelete1) We don't break software; the software was broken when we got it.
2) We don't create tests designed to cause failure; we create tests designed to expose the failures that are lurking.
3) The illusion that the software wasn't broken and the illusion that we're creating failure are among the most important illusions we testers need to dispel.
I'm delighted at the steady stream of excellent posts, and especially chuffed that it started to flow just after the Rapid Software Testing course in London. That was a rare group!
---Michael B.
Thanks Michael, Thank you for your support - and yes the RST course definitely helped motivate me! I recommend the course to testers, programmers and project managers!
ReplyDeleteI agree with your main point - that the software is essentially broken before it reaches the tester. The tester finds out that these problems are present in the system, and reports them.
1) In the blurb when I refer to breaking the software, I'm describing how the process appears to others. i.e.: "to a non-tester why you appear to be intent on breaking their..."
I tend not to use the phrase myself, except lightheartedly.
2&3) I'm not so sure about these... for example: a judgement, coding or configuration mistake was made before the system is examined by the tester - But the system may not 'fail' until we perform certain actions. By fail I'm thinking: Displeases or confuses user, performs slowly, crashes or loses data etc.
The incident on the Silver Bridge springs to mind (http://en.wikipedia.org/wiki/Silver_Bridge#Wreckage_analysis ) A contributing factor in the bridges 'failure' was a problem in the manufacture of a constituent part. Although this problem was in the system for many years, along with others such as a lack of redundancy, they did not 'fail' until December 15 1967.
If we were testing such a system, might we not add higher than expected load in an attempt to 'cause a failure'?
Though I can see that this engineering style language in a software setting is far from a perfect fit. Issues such as corrosion and decay don't apply. Though unplanned-for user load and change in usage do apply. I'm going to think about this...