[YourDadVPN]

Well, almost. I use a lot of assertions to check the obvious (value out of range, null pointer, etc.) and test the happy path(s) to prove the code at least works in the cases I can anticipate. I add unit tests for complex algorithms, and to prove a reported bug is what I think it is and that it has been fixed. Otherwise, I think using unit tests to find bugs is mostly busywork.

For even a fairly trivial piece of code, the search space for bugs can be vast or even infinite. Writing unit tests to find bugs within that space is like throwing darts at an infinitely large wall and trying to hit an unknown number of invisible targets. You can only write tests for the potential bugs you anticipate - if you could anticipate a bug, you wouldn't write it, right? You end up with dozens or hundreds of tests that probably never failed, except when you have to change something. Such was my experience when I tried to maintain high code coverage. When I switched to writing assertions and acceptance tests, my rate of bug reports did not change, and I was more agile.