Sunday, November 18, 2012

Testing Towers

I typed into Google the following:

"We test software to"

And read the results. I took some ideas from these results, and some of my own, and started to write down reasons to test. Things that motivate testers. Then I put them in an ordered list... looking at the list now it looks like I put them in (arguably) order of lowest to highest risk, the most important (to some imaginary business developing the software) at the bottom and what is considered the "icing on the cake" at the top. I looked for priority, and I looked for context, and I came up with a lot of different building blocks. Here are some:

Good User Experience (product is easy and/or fun to use, even if it doesn't do what is required)

Product Solves Problem (product solves the problem it was set out to solve, in that the functionality it has actually fixes the problem that existed that the product was made to fix)

Product Has Fewest Number Of Bugs (the highest possible number of bugs has been found, leaving the fewest number remaining in the software)

Product Won't Do Bad Things In Production (the product doesn't do anything that would

Product Is Reliable (product doesn't crash, shut down, run slowly, fail)

Product Won't Kill People (doesn't fail, causing death or serious injury)

Product "Works" (is operational. The buttons work, the functions do something)

I'm Learning (I know nothing directly about the "quality" of the product as a result, but I know more about the product, so I understand better what a "quality" product would mean)

Manager Isn't Bothering Me (ignore the software, I have my manager off my back)

Fulfils Requirements Doc (does what the documentation says it should)

Product Is Testable (product can actually be tested)

Based on context (software development methodology, culture, strategy, resources, and a host of other things) these could be stacked in multiple ways. You might want "product won't kill people" in there specifically because you're testing a safety-critical product. But if you're testing military weaponry perhaps you want your product to be able to kill people. It could be that Product Is Testable is on the bottom as it's required to test that it Fulfils Requirements in documentation and has the Fewest Number of Bugs which thus Solves The Problem. Personally I think that would be appalling in all sorts of ways, but it might be what your testing tower looks like. Like this:

Solves Problem
Fewest Bugs Fulfils Requirements Doc
Product Testable

Unfortunately I'd say that the Fewest Bugs block doesn't really exist. I'd say that the idea of finding a quantum quantity of bugs in an infinite test space is nonsensical. *POOF* it's gone, and the Solves Problem brick is unstable and could fall at any second! I'd say also that Fulfilling Requirements Doc does not support the solution of the test problem, but only the solution of the requirements doc, which is not the same thing. *CRACK*, it's broken. And the whole (if overly short for this example) testing tower comes tumbling down. Oops.

We all test to investigate the software, but what are you investigating? What is your aim? Something worthwhile I hope.

So, what are your bricks? Are they strong ones that support the layers above? Are they in the correct order, so as to stop your tower being top-heavy? Do they even exist in your tower (apply, and logically follow, in the real world)? It's an interesting way to see your processes, and the dependencies in your workflow, and what you're trying to achieve by testing the product, and for whom you are testing it. I wouldn't use it for modelling your desired practices, personally, but it does give some insight into these things, and possibly even the culture and practice of your company, and where things could be improved. Build your tower, and see if it has a worthwhile top to climb to. Then throw logic at it and see if it's still standing.

If you're looking for more (or better) bricks you might turn to something like James Bach's CRUSSPIC STMPL quality characteristics heuristics, or his CIDTESTD project environment heuristics. You could take stock of your resources, or learn about a software development methodology that you don't use.

What does your testing tower look like?

Thinking about this recently I've used the blocks to identify the divergence from why we should test to why we DO test and the importance of company culture. Strategy, planning, learning... all vital to set out what we should do. Add a layer of culture, habit and company practices and you get what we ACTUALLY do.

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