Your test coverage might be very high, but it's possible that your tests wouldn't notice if you deleted some code. Let's check for that automatically!
How I had to fix zimmski/osutil in order to write the Mutation Testing post.
An attempt at explaining שיטת מצליח, a method to take advantage of people not paying attention.
(Hebrew) The tale of my now-defunct android app for fetching public transport information.
When I helped a non-programmer friend with some code for psychology research, and how we avoided using Matlab.