Interview with Donald Knuth (InformIT)

If you read the interview again, you might note that he doesn't write that test suites are bad
in general -- he writes that *his* development style doesn't fit with unit tests a la JUnit or
so.

Please remember: TeX was probably the very first open source program that ever came with a
test suite, the trip test, and where every port must pass this torture test, otherwise it
can't be named TeX. And the trip test was already there in 1978. I'd like if half of the other
open source software would have test suites that are 10% as good as those of TeX and friends.

And I don't know what you mean with "weird restrictions". If you mean the overall usage of
global variables, reluctance to use structures, and other stuff that's not up-to-par with our
current software methods -- that's caused by the restrictions of Pascal compilers at the time
of TeX's creation. Back in 1981/1982, when we did our first TeX port, we actually had to
change the Pascal compiler to be able to get TeX running.