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Testing a maybe with machine learning.

“I figured it was just a jumbo jet.”

My son and I shake our heads & then adopt blank stares as if a non-body-snatcher has been
exposed in our midst.
“Twin engine,” I utter, as I glance skyward again.
“Single decker” My son adds as an explanation.
“It’s a plane”, she retorts, rolling her eyes.
My wife, (who is far smarter than myself) lacks my son and I’s ability to recognise aircraft. She has the typical persons ability to recognise aeroplanes. I grew up around airforce bases. I had a father who was an aircraft engineer. Years of exposure and explanations regarding aeroplanes, their mechanics and features.

My son is an avid flight sim game player and has consumed many hours of relevant youtube material on the subject. He also had the luck/misfortune of me discussing the planes that frequent the skies, above us here, near London.
Given our combined experience & expertise, we probably have a reasonable ability to recognise the make & model of the planes we see in the sky. I would h…
Recent posts

Betting in Testing

“I’ve completed my testing of this feature, and I think it's ready to ship”
“Are you willing to bet on that?”
No, Don't worry, I’m not going to list various ways you could test the feature better or things you might have forgotten.
Instead, I recommend you to ask yourself that question next time you believe you are finished. 
Why? It might cause you to analyse your belief more critically. We arrive at a decision usually by means of a mixture of emotion, convention and reason. Considering the question of whether the feature and the app are good enough as a bet is likely to make you use a more evidence-based approach.

Why do I think I am done here? Would I bet money/reputation on it? I have a checklist stuck to one of my screens, that I read and contemplate when I get to this point. When you have considered the options, you may decide to check some more things or ship the app. Either could be the right decision.
Then the app fails…
The next day you log on and find that the feature is b…

Software development is in the Doldrums

"Don't get off the boat."

"Seriously, never get off the boat," The instructor said, leaning forward and looking at each of us in turn.

"But surely if it's sinking..." We reply, somewhat confused and slightly incredulous. We've seen Titanic, we think to ourselves, we know how this sea survival stuff works...

"OK" He concedes, If things get really bad, "Get on the life raft if you can step-up from the boat to the life raft".

"But, But... the yacht is like 37ft long, Do we want to wait until that whole boat is lower than the life-raft? When less than 1ft of the yacht is above the surface? Meanwhile all the time the life raft is just there... floating happily alongside."

"Pretty much, yes," he said nodding.


That was about 15 years ago. Not much has changed since. The reasons are manifold. Firstly, the yacht is a decent shelter. The thin plastic of a legal minimum life-raft isn't going to protect you fro…

A h̶i̶t̶c̶h̶h̶i̶k̶e̶r̶'s̶ software tester's guide to randomised testing - Part 2

How would test a water sac? (Wow there, calm that tester brain... I know what you are thinking, Whats it used for? Who / what uses it? how long does it need to last? Does the temperature of the water matter?  Is it single use? etc. But let's assume a generic hiking or camping water sac for now) I'm guessing one of your suggestions includes filling it with water, shaking it a bit and checking for leaks.

Seems kind of obvious right? but when it comes to software, we often do away with old-fashioned techniques such as filling something up and looking at it. Where's the machine learning test algorithm? Call this a BDD scenario? Can Selenium check for H₂0? I have to run this past the B.A...


We can treat randomly generated test data and inputs in much the same way as water. Data files or other inputs like user interactions are the ever-moving parts of our applications. Think about it, the code is entirely static - it's the state or data that is changing. This contradicts the…

A h̶i̶t̶c̶h̶h̶i̶k̶e̶r̶'s̶ software tester's guide to randomised testing - Part 1

Mostly Harmless, I've talked and written about randomisation as a technique in software testing several times over the last few years. It's great to see people's eyes light up when they grok the concept and its potential. 
The idea that they can create random test data on the fly and pour this into the app step back and see what happens is exciting to people looking to find new blockers on their apps path to reliability.
But it's not long before a cloud appears in their sunny demeanour and they start to conceive of the possible pitfalls. Here are a few tips on how to avert the common apparent blockers. (Part 1) Problem: I've created loads of random numbers as input data, but how will I know the answer the software returns, is correct? - Do I have to re-implement the whole app logic in my test code?
Do you remember going to the fun-fair as a kid? Or maybe you recall taking your kids now as an adult? If so then you no doubt are familiar with the height restriction -…

How did you find that bug? Are we sitting comfortably, then I'll begin.

How did you find that bug? - They asked with a sort of puzzled "he dun't thunk like uz" look on their faces. An expression that suggested they were unsure whether to commend the discovery or gather their pitchforks and organise a well overdue witch burning.

Likewise, I now knew why they needed me. The team members were genuinely hard working people trying to build something new and exciting. But they lacked one thing, someone exploring & asking questions - trying to find out new things about their application. Exploring is literally a step into the unknown, and that can be uncomfortable for those not experienced in how to do it well.
So how did I find that bug? It's easy to tell a story of how I tried that particular input value because... Paragraph 3 of v4.6 of the requirements document stated that the user shall indeed on occasion X given input Y in Chrome v62 do... Or spout some other overly verbose explanation of why that broken 'scenario' came to be…

Was there a test for that? No, and there shouldn't be.

The release shipped. For a while, the team felt good. The work was done, the team had achieved something, and that was rewarding. 
Unfortunately for the team, it wasn't long before a problem was found. The Product Owner wasn't happy and had asked was going on down there in the galley, do we need new coders? Better ones? Hipster coders?
After an investigation, some blushes, raised eyebrows and a couple of "Oh... Yeeeah's" they found the cause. A confusion had collided with a bodge, and the result was a mess. Should they write an automated - test for this problem?  An embarrassing mistake or a misstep can make us feel we have to do something. An action greater than a fix is needed. A penitance needs to be performed, to redeem ourselves, to make us right again.
Sometimes the penitence is best spent adding a test for that issue. Especially if writing that test has a low cost, the frequency of the problem occurring is high or the impact of the problem is substantial.

B…