Exploration Through Example

Example-driven development, Agile testing, context-driven testing, Agile programming, Ruby, and other things of interest to Brian Marick

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Sat, 07 Jun 2003

Code Kata: Visualization

I really like this idea of Chad Fowler's.

## Posted at 18:00 in category /misc [permalink] [top]

Octopus eyes and agile testing

The story I've heard about octopus eyes goes like this: human eyes have blood vessels and nerves on the top, the side toward the lens. Octopus eyes have them on the bottom. The octopus design seems obviously better (though that's disputed): why put crud between the light receptors and the light source?

One point of the octopus eye story is that chance decisions linger. At some point, some ancestral critter "chose" a particular orientation for some particular type of cell, and here we are, so long later, stuck with crud in our vision and a blind spot where the nerves punch through to the brain.

Many in the testing world are scornful of test-driven design. "That's not real unit testing," they say. "Those people are ignorant of the testing literature." And some in the programming world are apologetic, saying things like "Of course, our tests would seem horribly inadequate to a real tester."

The assumption is that programmers should learn what the testers already know. As a tester, it's in my interest to agree. But what crud is in my vision because of chance decisions by my intellectual ancestors? It may have been a wonderful thing that Ward Cunningham, Kent Beck, and the other people who invented test-driven design had not read my book on programmer testing. Perhaps ignorance let them put the blood vessels on the bottom.

Today, agile testing is a hot topic. People are looking to augment programmer testing with equally successful customer-facing testing, and automated testing with exploratory testing. I'm pretty tightly tied to that effort. Does the above mean that I should say, "Go thou, programmers, and invent testing anew. I have nothing to offer you but intellectual corruption from a dead past."

Well, maybe. But I'm not gonna. What I will do, however, is hope that this summer's events make me discard some cherished beliefs. I'm going to be listening carefully to, and working closely with, people out of the testing mainstream. Not to teach, but to learn.

## Posted at 17:52 in category /testing [permalink] [top]