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by protomyth 3131 days ago
Tester worked a later shift (noon to 8pm) and was running scenarios. Got a really odd error that made contracted pricing incorrect. Developer came in the next morning and ran the scenario just fine. Tester repeated the scenario at 6:30PM and got the same error. Both thought the other was nuts and this went on for a week. Found out it was an interaction issue when using the time (UDT) to get the current market date.

Lesson: if anything goes wrong at night but not during the morning, look at all the date code.
1 comments
rmetzler 3131 days ago
I also found a test breaking on Mondays. Never on any other day. It tested a sum for the current week but made the mistake of creating models for "yesterday" which is on another week if it's the first day of the week (depending on location, Monday in Europe, Sunday in the USA).
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martinpw 3131 days ago
Had an office where, every Thursday, one developer's machine would reboot at the same time late in the evening. It didn't happen to anyone else. Eventually he decided to stay late one Thursday and watch it to see what happened.

At the appointed time the cleaner came by, unplugged his machine from the power socket and plugged in the vacuum cleaner to clean the room, and when done, plugged the machine back in.

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staikken 3131 days ago
Heard a similar story about a laboratory system with tight environmental controls. Every so often the humidity would spike and the room would go out of tolerance after typical work hours. The designers of the system were under quite a bit of pressure until someone finally stuck around long enough to catch the janitor mopping the floors.
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dvtv75 3131 days ago
Some decades ago, friends of mine ran an ISP that resold bandwidth from another business. They used a leased line to the business, and every Friday evening at about 7.30 their connection dropped out.

It turned out that the cleaners at the remote end would plug their vacuum cleaner into the same circuit that was powering my friends' hardware. The power surge caused their hardware to crash, and nobody had access to properly reboot it until Monday 8.30am.

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