DoesUnitTestingMissTheBigBugs

I had expected that doing rigorous unit testing would put an end to bug-fix hell. Now that my project is growing, the problem is that the difficult bugs to anticipate and fix are the ones that happen when components interact in unexpected ways. Since unit-testing exercises these components in isolation, the unexpected interactions aren't covered by the tests.

Is this a common problem? Or do acceptance-tests fill the gap? - PhilDawes

You are right full unit testing is no substitute for functional tests which test the integrated whole. I would say the introduction of automated functional-level acceptance tests are part of the answer to your bug problem. Try to get these defined up front by the customer with the story, to save requirements creep. - RachelDavies

Do you do 'acceptance test first'? I'm wondering this because since my project is free-software, I'm effectively the customer (at least initially). I've always looked upon acceptance tests as something the customer uses to prove that the software is what they want, rather than a means to limiting defects in the software. - PhilDawes

(I have examples if anybody's interested!) - PhilDawes ³host³³date³October 18, 2001³agent³Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.5) Gecko/20011012³DoesUnitTestingMissTheBigBugs