investigating software

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

Thank you to the colleague/customer/product owner, who found the bug I missed. That oversight, was (at least in part) my mistake. I've been thinking about what happened and what that means to me and my team. Giving thanks. It helps us remember. I'm happy you told me about the issue you found, because you... 1) Opened my eyes to a situation I'd never have thought to investigate. 2) Gave me another item for my checklist of things to check in future. 3) Made me remember, that we are never done testing. 4) Are never sure if the application 'works' well enough. 5) Reminded me to explore more and build less. 6) To request that we may wish to assign more time to finding these issues. 7) Let me experience the hindsight bias, so that the edge-case now seems obvious!

Google Maps directs me to and from my client sites. I've saved the location of the client's car parks, when I start the app in the morning - it knows where I want to go. When I start it at the end of the day, Google knows where I want to go. This is great! It guides me around traffic jams, adjusts when I miss a turn and even offers faster routes en-route as they become available. But sometimes Google Maps does something wrong. I don't mean incorrect, like how it sometimes gets a street name wrong (typically in a rural area). I don't mean how its GPS fix might put me in a neighbouring street (10m to my left - when there are trees overhead). I mean wrong - As in something unfair and socially unacceptable. An action, that if a person did it, would be frowned upon. Example: Let’s assume a road has a traffic jam, so instead of the cars doing around 60 mph, we are crawling at <10 mph. In the middle of this traffic jam, the road has a junction, an

After a weary few hours sorting through, re-running and manually double checking the "automated test" results, the team decide they need to "run the tests again!", that's a problem to the team. Why? because they are too slow. The 'test' runs take too long and they won't have the results until tomorrow. How does our team intend to fix the problem? ... make the tests run faster. Maybe use a new framework, get better hardware or some other cool trick. The team get busy, update the test tools and soon find them selves in a similar position. Now of course they need to rewrite them in language X or using a new [A-Z]+DD methodology. I can't believe you are still using technology Z , Luddites! Updating your tooling, and using a methodology appropriate to your context makes sense and should be factored into your workflow and estimates. But the above approach to solving the problem, starts with the wrong problem. As such, its not likely to find

“We got a good run from the tests” the tester stated. “So what’s the story?” the scrum master asked. “85% Pass” comes the reply, meekly. “OK, just need to fix that 5% then.” The scrum master announces before striding off to announce that the team is only a couple of % away from success. Our tester takes a moment to try and process the exchange… Firstly , their own words: “We got a good run” Why had they said that? Well - in a sense - it was true. They had executed the tests before, and they had returned a much higher failure rate. But the code being checked was the same... OK, so there were at least 3 obvious ways to interpret the data. The app code meets the criteria checked by the tests. ( Based on test run 2 ) The app code does not meet the criteria checked by the tests. ( Based on test run 1 ) The tests are as reliable a the toss of the coin. ( Based on both test runs ) Its surprising how unlikely people are to choose (3). Secondly , the scrum