investigating software

Many, Many years ago I worked at a startup called Lastminute.com (a European online travel company, back when a travel company didn't  have to be online). For a while, I worked in what would now be described as a 'DevOps' team. A group of technical people with both programming and operational skills. I was in a hybrid development/operations role, where I spent my time investigating and remedying production issues using my development, investigative and still nascent testing skills. It was a hectic job working long hours away from home. Finding myself overloaded with work, I quickly learned to be a little ruthless with my time when trying to figure out what was broken and what needed to be fixed. One skill I picked up, was being able to distinguish whether I was researching a bug  or trying to find a new bug. When researching , I would be changing one thing or removing something (etc) and seeing if that made the issue better or worse. When looking for bugs , I

A while back, I sat in on a planning meeting. Many planning meetings slide awkwardly into a sort of ad-hoc technical analysis discussion, and this was no exception. With a little prompting, the team started to draw up what they wanted to build on a whiteboard. The picture spoke its thousand words, and I could feel that the team now understood what needed to be done. The right questions were being asked, and initial development guesstimates were approaching common sense levels. The discussion came around to testing, skipping over how they might test the feature, the team focused immediately on how long testing would take. When probed as to how the testing would be performed? How we might find out what the team did wrong? Confused faces stared back at me. During our ensuing chat, I realised that they had been using BDD scenarios [only] as a metric of what testing needs to be done and when they are ready to ship. (Now I knew why I was hired to help) There is nothing wrong with c

Is your car German or Japanese? Are your chocolates from Belgium? And your wine, which country might that be from? There's a good chance you know the answer to some of those questions. Our culture places value on provenance. That is, we care where our possessions originate. It's something we tend to notice. Warning label? Furthermore, we ascribe, often without our notice, characteristics to things because of their provenance. For example, that's a Japanese radio - its reliable but not cheap, etc. I often do this un-empirically, without measurement or examination. (that's a flaw) For software testing, our automatic identification of provenance can be both a useful tool and a distraction.  Noticing where or from whom a feature originated can be enlightening. You may learn over time that a particular team or person tends to implement certain things well, and others things not so well. This has a tendency to help me to find some bugs relatively easily w

Heraclitus wrote these words 2500 years ago: "Ever-newer waters flow on those who step into the same rivers." or paraphrased in more colloquial English: You never stand in the same river twice. Known as the "The obscure one" to some of his contemporaries, he was known to make statements that were considered paradoxical and sometimes unhelpfully contradictory. I don't know about you  - but sometimes when discussing testing feedback - I feel like I am channeling the ghost of Heraclitus. His comments regarding walking through rivers are an apt description of our work with software and its versioning. Do we ever play with the same app twice? On a trivial level, we do. When we widen our view we can see that the waters have moved on. For example,  The time has changed. It may even have gone back to a previous date and time.  The code is probably located in a different memory location.  The app and operating system are probably facing different types of

Take a pack of cards, shuffle them well, and place them on the desk in front of you. Could you accurately tell me what the order of the cards would be, without looking?   By Rosapicci - Own work, CC BY-SA 4.0 Now spend 2 weeks in a software development team, writing code & using services, and deploy that code to your cloud server environments. Could you tell me where the bugs would be, before looking? In both cases we have a rough idea of what’s in the product at the end. But the detail, how its actually going to play out? we have no realistic idea. Skeptical? Take the playing cards… If we lay the cards out one card at a time. Then the order in which they are laid out, has probably never been seen before. Ever.The number of permutations of the well-known 52 playing card pack is 80,658,175,170,943,878,571,660,636,856,403,766,975,289,505,440,883,277,824,000,000,000,000. OK, now let’s get back to our code. Even trivial apps, include dozens of code libr

Shutter sync is an interesting artefact generated when we video moving objects. Take a look at this video of a Helicopter taking off: Notice how the boats are moving as normal, but the rotors appear to be barely moving at all. This isn’t a ‘Photoshop’. It’s an effect of video camera’s frame rate matching the speed/position of the rotors. Each time the camera takes a picture or ‘frame’ the rotors happen to be in approximately the same relative position. The regular and deterministic behaviour of both machines enables the helicopter to appear to be both broken and flying. The rotors don’t appear to be working, while other evidence suggests its rotors are providing all the lift required. What's so exciting is that this tells us something useful, as well as apparently being a flaw or fail. We could both assume the rotors move with a constant rotation, and estimate a series of possible values for the speed of the rotors, given this video. Your automated checks/tests can

I remember teaching my son to ride his bike. No, Strike that, Helping him to learn to ride his bike. It’s that way round – if we are honest – he was changing his brain so it could adapt to the mechanism and behaviour of the bike. I was just holding the bike, pushing and showering him with praise and tips. By 齐健 from Peking, People's Republic of China (Down the Hutong) If he fell, I didn’t and couldn’t change the way he was riding the bike. I suggested things, rubbed his sore knee and pointed out that he had just cycled more in that last attempt – than he had ever managed before - Son this is working, you’re getting it. I had help of course, Gravity being one. When he lost balance, it hurt. Not a lot, but enough for his brain to get the feedback it needed to rewire a few neurons. If the mistakes were subtler, advice might help – try going faster – that will make the bike less wobbly. The excitement of going faster and better helped rewire a few more neurons. Whe