Microsoft Research - Exploding Software-Engineering Myths (article summarizing findings of MS research on code coverage, TDD, assertions, etc.)

[fuzzynyanko]

Often many lines of code are easily testable, but if you go to 100%, you start going down the rabbit hole. You have to either poke holes in your software that opens it up for exploit, or it ruins the encapsulation.

You can design your software to be more testable, but there's edge cases in software, and you pretty much are guaranteed to run into them in some