Consider the Lowly Calculator App …

Yesterday, Ben Kelly, the most famous context-driven tester in Japan(*), tweeted a link to a reddit where (apparently) a programmer was asking for help testing a website. He couldn’t possibly test it in time and wondered if Selenium would help.

Here’s what Ben tweeted:

So many ways one could answer this. Urge to rant...rising... http://www.reddit.com/r/softwaretesting/comments/1ridi3/how_to_automate_testing/ …

Ben was concerned the whole post was a troll – 15 seconds of faux-ignorance about testing that would leave to a huge argument. I didn’t know what was going on either, so I waited for an evening, then came in this morning and posted my reply. Here’s the part that I really enjoyed writing:

Consider the lowly Calculator app: You ‘should’ test 1+1, 1+2+, 1+3, 1+4 … essentially infinite. Then there’s 2+1, 2+2, 2+3,2+4 … up to n+1, n+1. Infinite time infinity. Now consider /state/: 1+1 puts us in the ‘state’ of 2 – what if there is a small memory leak there? It happens. That means the sequence of 1+1, then /that/ 2+1, will be different than 2+1. So you’ve got to test … and then there’s fractions … and the * and – and / and …

It’s turtles all the way down …

If you’d like to read the entire reply, it is up on reddit right now.

–heusser

(*) Addendum: After four years in Japan, Ben moved to London months ago. I need to find a new nickname for him.

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