Testing and the Parable of the Painter

One of the many stories from the real world is having a coworker who doesn't understand the idea of how to test an application.  When asked to write a test program, they think that means writing a second program with the same logic - which is redundant of course - and any other approach makes no sense.

Here is a story to tell these folks.

There were two painters who kept busy painting houses around town. The painters were brothers named Jerry and Dale. They'd come by the house to be painted and the owner would tell them what color to use, the people in town didn't have eclectic tastes which made it easy for the men, the choices were: white, blue, red, or yellow. They had both been painting for many years and made a comfortable living this way.

A retired sea captain moved to town and bought an older house that was in dire need of a paint job.  He hired Dale to paint his house with instructions to paint the house ocean blue. The captain had bent Dale's ear about how the sea was his first love and she showed many different faces and that you could encounter waters of midnight blue during a storm or nearly turquoise near a shallow lagoon on a sunny afternoon.

Dale goes back to his shop, picks up his blue paint, telling himself that blue is blue, and heads off to do the job. When he's done the captain comes around, takes one look at his house and exclaims, "I've never seen the wild ocean look like that! I said ocean blue, not sky blue!".  The captain dismissed Dale and refuses to pay.

Dale returns home and grumbles to his brother Jerry about the whole affair, "If he wanted a specific shade of blue he should have said so before I painted the whole house!"

The next day, Jerry is surprised to find the very same captain at his door asking to have his house painted a, "proper shade of ocean blue."  Jerry, with the hindsight of his brothers experience, takes the captain to his paint shed and quickly mixes several different shades of blue until the captain smiles and says, "That one reminds me of calm seas off the coast on a sunny day, I'll take it.".  Jerry splashes the chosen color onto a thin peice of wood and the two men agree on a price. The captain directs Jerry to get started the next day while he is away at the docks helping a friend repair a fishing boat.

The work goes quickly and when the house is done Jerry goes to fetch the captain to ask him to come see the finished product. On the way to the docks the sky darkens and starts to fill with ominous clouds, a storm is headed this way. Jerry finally reaches the docs and finds the captain in a sour mood, the captain snaps, "It had better be the right color, I'm not going to live in a house that doesn't remind me of the fickle sea."  Upon seeing his house the captain throws a fit, "That is not the color of the ocean! What kind of painter are you? You're not going to get one cent out of me for such a lousy job". He continues his verbal abuse until Jerry pulls out the peice of wood with paint splattered over it and holds it up saying, "You recognize this?  This is the color you agreed to before we started.  When I hold it next to your house, you can clearly see that they are the same color.  You might have changed your mind but I've held up my end of the bargin and expect to be paid fair-and-square.  If you want it painted some other color, I'll be happy to add as many coats as you have money to buy, but you'll have to pay for this one first."   

The moral of the story? Agreeing on the outcome beforehand is the only way to prevent any arguments over what 'done' means at the end.