Interview with Donald Knuth (InformIT)

A testsuite, let us not forget, whose values were determined the way 
values in testsuites *should* be determined, by working out in some other 
way (in this case by hand) what the values shold be and plonking them in.

I have seen all too many testsuites in which this is not the case. (Oddly 
enough, these tests rarely fail, unless run in a universe in which 1 != 
1.)