- For your amusement...
  - The lamest excuses for not testing a primitive:
    My primitive tests itself.
      (Unless it is BLD or UNITTEST, this isn't the case)
    I tested it when I wrote it.
      (And someone modifies it 6 months from now and...)
    It works on my system.
      (The field system is missing some old bug fixes)
    My code is bug-free.
      (Yes, keep telling yourself that...)
    My dog ate it.
      (Didn't work then, doesn't work now)
  - A few valid exceptions where automated testing doesn't work well:
    Graphics and user interfaces.
      (Must be manually tested)
    Network interfaces.
      (Testable, but requires setup)
    Error handling.
      (Some errors are extremely hard to reproduce)