Pushing boundaries at airports
Submitted by Erik Petersen on Fri, 18/01/2008 - 13:19.
ethics | heuristics | perspectives
Not all bugs are created equally. One of the most common bugs is all about equality, too much or not enough. It is caused by code being “off by one”, where a boundary is meant to be at a particular point but is one value too high or too low, for example >=5 (5 or greater) instead of >5 (greater than 5).
Two incidents at airports had me inadvertently testing for boundary bugs. I had dropped off someone at the airport, waited for their delayed boarding and returned to the car park. Parking was $10 for up to an hour, then $18 dollars for up to 2 hours. I paid my ticket at a machine at 61 minutes, and paid $18! Damn. That boundary was spot on.
That wasn’t as painful as another time, getting into the checkin queue a few minutes before the half hour baggage cutoff. I waited a minute or so, and the attendant started to check me in then apologized that the system was preventing her completing it because the half hour boundary had just been crossed. I ended up bumped to the next flight leaving in another 2 hours. Even worse, she explained that if I had checked in at a kiosk instead of queuing, she could have checked my bags in and got me on that flight. At another time I might have been interested in my inclusive interpretations of their exclusive boundary (queue before cutoff versus be at counter before cutoff vs. be checked in manually by cutoff vs. kiosk checkin). That was beyond the bounds of common decency, but the program overruled any staff sympathy, though there was empathy. I just wandered off into a fog of unbounded apathy, which had no equal. I found no bugs but both situations certainly bugged me! [grin]
Read a great article about boundary testing here