[Haskell-cafe] Tutorial on Haskell

Chris Kuklewicz haskell at list.mightyreason.com
Wed Apr 18 06:41:42 EDT 2007

Dougal Stanton wrote:
> *QuickCheck is a really powerful way to work.*
> The real pain in the butt with unit tests is having to write the damn
> things. Especially for corner cases - if they were easy to reason
> about they wouldn't really be corner cases, would they? QC allows you
> to sidestep that neatly by generating a set of unit tests from a
> specification. And often generating cases you *wouldn't* have thought
> of yourself. Genius!

For the regex-tdfa project, the unit tests from the AT&T site defined important
semantic corners that some implementations got "wrong".

Once I had code that worked with *all* those examples, the QuickCheck generated
strings and regular expressions made for some quite weird random tests that
still found holes in my code.

And holes in the TRE c-library code.

And holes in the standard c-library regex.h of OS X 10.4.x.

So I am quite impressed by Quickcheck.


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