Subject: Re: who's running your business?
From: kragen@pobox.com (Kragen Sitaker)
Date: Wed, 31 May 2000 16:15:45 -0400 (EDT)

I'm reluctant to publicly disagree with luminaries such as Ian, because
I'm usually wrong when I do, but I'll do it anyway.

There are some kinds of bugs testing is very poor at finding.  Even
exceptionally good testing --- meaning full code-coverage testing, plus
spec-coverage testing (I'm not sure of the term for this) where you
test each variable having each of the meaningfully-different sets of
values it can have --- e.g. for division, you want to test cases where
each of the numerator and denominator is positive, negative, and zero,
plus stochastic use-case-based testing --- will be unlikely to find
certain kinds of tests.

Furthermore, such extreme testing is very labor-intensive.

Reading code critically is likely to expose different sorts of bugs
than testing it.  Doing both together is likely to expose more bugs
than either alone.

All of this is well documented in that famous journal, _Somewhere In
The Literature_.  :)

-- 
<kragen@pobox.com>       Kragen Sitaker     <http://www.pobox.com/~kragen/>
The Internet stock bubble didn't burst on 1999-11-08.  Hurrah!
<URL:http://www.pobox.com/~kragen/bubble.html>
The power didn't go out on 2000-01-01 either.  :)