Skip to main content

Believing you don't know

People want to believe. If you are a tester then you've probably seen this in your work. A new build of the software has been delivered. "Just check it works" you're told, It's 'a given' for most people that the software will work. This isn't unusual, it's normal human behaviour. Research has suggested that it's in our nature to believe first. Then secondly, given the opportunity, we might have doubt cast upon those beliefs.

We see this problem everywhere in our daily lives. Quack remedies thrive on our need to believe there is a simple [sugar] pill or even an mp3 file that will solve our medical problems. Software like medicine is meant to solve problems, make our lives or businesses better, healthier. Software release are often presented to us as a one-build solution to a missing feature or a nasty bug in the code.

As teams, we often under-estimate the 'unknown' areas of our work. We frequently under-estimate the time taken to test and fix the features we create. I suspect the more 'unknowns' we can think of the less we actually prepare for them. We fail to see the potential link between the idea of an 'unknown' and its inherent ambiguity (It's unknown for a reason - probably the new function is not easy to 'know' or understand). As such, many development projects will deliberately avoid planning for the fixing of bugs. Refusing to accept that they can be accounted for until they 'exist'. Not realising that ambiguity, issues and bugs almost always do get uncovered, and therefore already 'exist' before a single line of code is written.

Even disciplined teams will often slip into their 'belief system' when the names are changed. For example, A new feature may be tested thoroughly, but a series of major 'bug-fixes' to the same system skip through testing with barely a glance. For all we know the programmer checked in the 'old code' and the feature is now completely gone! Even if you have an acceptance test in place - every non-acceptance tested execution path maybe broken!

In the software business we are starting to be seen as quacks. We often churn out half baked remedies that don't meet the customers needs. The customer can't even look at the label, and see the possible side effects. The testing has been so cursory and confirmatory that we didn't find any issues (There it is again: Lots of unknowns=no problems). If a doctor gave you a potent medicine, and when you read the label it didn't mention a single possible side-effect, would you really believe it was 100% safe?

The same applies to software... Until we question the hypothesis that it's all going to be OK; Until we put our proposed solutions through a 'trial' with testing, then we will remain charlatans. This questioning process can't be a series predefined checks. Much as a medical trial should not be to check that a drug like Thalidomide is -only- a potent antiemetic, or that an antibiotic like Penicillin was -only- 'good'. We'd hope they would check the drug for other potential problems, look deeper and learn about it's good and bad attributes, by building and testing hypotheses as they learn.

Comments

  1. Pete, you are spot on.
    Making the comparison between sw development and quacks is going to put some people off. Is it that bad? Yes, I'm afraid it is!
    Software engineering is in a crisis - we're taught to think everything is possible. Even testing to ensure bug-free software.

    ReplyDelete
  2. Good point Anders, Yes, there's a failure to know our own limits and our own flaws. I studied computer science, but looking back now I can see there was very little 'science' involved in the course.

    One of the most useful minor courses I took was in cognitive psychology, I think that has helped me at least as much as the technically focused CompSci courses.

    The introduction to how visual illusions and our assumptions affect our perception-unconsciously, is very relevant to software testing. Knowing what humans are capable of and how we are 'incapable' is essential.

    ReplyDelete
  3. Could we perhaps label this as 'belief bias' to complement the plethora of other biases out there?

    ReplyDelete

Post a Comment

Popular posts from this blog

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 -…

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…