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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Fri, 25 Jun 2004

At Agile Development Conference 2004: ownership

For whatever reason, I was in a scrappy mood this afternoon and evening. And I took offense to the word "own", as used - for example - in this statement "... and the customer owns the acceptance tests".

I have yet to think through my objection, but it's somewhat summed up in the remark I made twice today: "If she owns them, how much can she sell them for?"

Ownership is all about a culture of scarcity and exclusion, not a culture leaning toward abundance and sharing. You own something if you can prevent someone else from using it. Why is ownership a useful metaphor within an agile team?

## Posted at 07:50 in category /adc2004 [permalink] [top]

At Agile Development Conference 2004: the Blindfold Game

My faithful reader will recall that Elisabeth Hendrickson and I were running a tutorial on exploratory testing, but we wouldn't actually test software. Instead, we would have people create a game that they would then test.

Here's an interesting game that one team created. It was intended to demonstrate the value of rapid feedback. It consisted of two teams of two people. A team consisted of a car and a driver. The "car" was blindfolded. He or she moved in a particular direction until commanded otherwise by the driver. The driver could issue commands at fixed intervals, with one exception: if the car was about to damage itself, the driver could say "stop!" Then they would have to wait for the end of the interval for the next command. We didn't want anyone to tumble off the balcony to the ground floor.

Each team had to make it to a gas station. "Gassing up" was represented by a small tented card. The first blindfolded person to pick up the tented card was the winner.

The trick is that one driver could issue commands every twenty seconds, but the second could do it every five seconds. That is, one car had more frequent feedback. Guess which one won?

Yes, it was the one with more rapid feedback. I thought this game worked nicely. For a team whose whimsicality hadn't been beaten out of them, it would be a fun introduction to the virtues of rapid feedback. Give it a try!

There was one interesting twist. We ran a trial of the game in which the intervals were reduced. The five-second car now got instructions every second. The 20-second car got instructions every five seconds.

I'd been the five-second car, now the one-second car. Our team noticed two things. One was that the stress level increased dramatically. Both I and the driver got flustered keeping up with the demands of the clock. The other was that we didn't beat the five-second person by much.

Does this tell us anything about iteration length? Beats me, really. But I have heard comments that make me think that one week iterations are too short for some people, that they feel they don't really get a chance to get into the flow before they have to switch direction. They might well be able to learn to be comfortable with one-week iterations: but is it possible that a given team has a "natural" iteration length that it needs to discover?

## Posted at 07:50 in category /adc2004 [permalink] [top]