[Haskell-cafe] HSpec vs Doctest for TDD

[Alois Cochard]

I'm not replying to you nor Michael Orlitzky.
I'm replying to Richard A. O'Keefe.

You can see that by looking at which message was quoted below my actual
response.
I hope it will make things clearer, because I'm actually not arguing at all
against what you are saying :-)


On 26 June 2014 13:44, Erik Hesselink <hesselink at gmail.com> wrote:

> On Thu, Jun 26, 2014 at 2:24 PM, Bob Hutchison <hutch-lists at recursive.ca>
> wrote:
> >
> > On Jun 26, 2014, at 3:10 AM, Erik Hesselink <hesselink at gmail.com> wrote:
> >
> >> On Wed, Jun 25, 2014 at 5:47 PM, Michael Orlitzky <michael at orlitzky.com>
> wrote:
> >>> On 06/25/2014 11:24 AM, Francesco Ariis wrote:
> >>>> On Wed, Jun 25, 2014 at 02:45:37PM +0200, Mateusz Kowalczyk wrote:
> >>>>> While I disagree with initial view that testing is useless, I
> certainly
> >>>>> disagree with this approach too. There are plenty proof-assistants
> using
> >>>>> type-checking to prove programs correct. That's not to say Haskell
> >>>>> itself is suited for such task. If you have a type system strong
> enough,
> >>>>> classical tests are no longer required because you can encode all the
> >>>>> properties you need in types proving at compile time that your
> program
> >>>>> is in fact correct.
> >>>>>
> >>>>
> >>>> For non-believers, here is a blog post that opened my eyes on the
> matter [1].
> >>>>
> >>>> [1] http://lambda.jstolarek.com/2013/12/data-is-evidence/
> >>>
> >>> None of that helps if you write the wrong program. Your program may
> >>> typecheck, but if you're expecting "42" as output and your program hums
> >>> the Star Trek theme instead, the fact that it correctly does the wrong
> >>> thing won't be much consolation.
> >>
> >> The same goes for any kind of testing, though. All these (writing the
> >> program, giving types for the program and testing the program) are
> >> different ways of specifying the same thing. The benefit from doing it
> >> twice in different ways, is that it's unlikely that you'll do it wrong
> >> twice *in the same way*.
> >
> > So, tell me about QuickCheck… why is this thing thought so highly of?
> (this is a rhetorical question, I don’t need an answer :-)
> >
> > The problem isn’t really the unexpected humming of a song. It’s
> answering 43 when you’re expecting 42.
>
> Are you replying to me, or Michael Orlitzky? Because I'm not sure what
> point you're making. I'm not arguing against the use of tests *or*
> types. I'm just saying neither is going to give you complete
> guarantees, but using either one is already much better than using
> none.
>
> Erik
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-- 
*A\ois*
http://twitter.com/aloiscochard
http://github.com/aloiscochard
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