I contribute to an open source project to build a decentralized secure storage system: https://tahoe-lafs.org .

Our comprehensive unit tests are invaluable for finding bugs, and we run them every time we commit a patch, on all supported platforms, but they take too long and this interferes with development flow.

This is especially a problem on the laptop of one of the lead developers, Brian Warner, who is using OS X with some sort of full-disk encryption that makes his disk I/O slow. But it is also a problem on everyone else's development machine and on the buildbots.

Therefore, I'm offering a 50ⓑ bounty to the first person who submits a patch which causes the tests to take only 4 minutes 30 seconds (approximate) instead of 24 minutes (approximate) on Brian's laptop.

More info here:

https://tahoe-lafs.org/pipermail/tahoe-dev/2012-April/007314.html