Re: [HUnit-users] automatic suite statements?

[Shae M. E. <sh...@Sc...>]

Dean Herington <her...@cs...> writes:


> If you mean that you'd like simply to add the top-level definition for a new test
> case and have it included automatically in the set of tests to be run by HUnit, the
> answer is "no".  Haskell doesn't provide the reflection capabilities needed to do
> this.  With HUnit, you must construct the set of tests as a data structure.  (On
> the plus side, it's so much easier to construct test suites as data structures in
> Haskell.)

Rumor on the #haskell irc channel is that Template Haskell will allow for
compile time reflection, I'm looking forward to that.

> But if you find it inconvenient to define a test case and separately add it to a
> test suite, there's no reason you couldn't simply define your new test case
> directly in the data structure representing the suite.  Something like:
> 
>     suite = test [
>       ... test 1 ... ,
>       ... test 2 ... ,
>       ... test 3 ...
>       ]

That's an excellent idea, thanks. This covers what I want.


By the way, if you wish to use Hat 2.00 with HUnit, you need to apply the patch
below because Hat isn't flawless yet.

<paste>

> /home/shae/src/haskell/libraries/THUnitText.hs:64:
>     Variable not in scope: `TPrelude.fnegate'

The problem here is with hat-trans - in the following definition,

    put line pers (-1) = do ...; return (-1)

it has mistakenly interpreted the negative number literal on the left
hand side as a variable binding for negate.  Hence, in the transformed
version of the code, it has used the lambda-bound form `fnegate'
on the right, instead of the real let-bound variable `gnegate'.

Until we can find a fix for hat-trans, here is a workaround for your
application.  Replace the negative numeric literal pattern with another
form, such as a guard.  For instance:

--- HUnitText.lhs	Thu Feb 21 20:21:13 2002
+++ HUnitText.lhs.new	Fri Jul 26 10:43:40 2002
@@ -55,7 +55,8 @@
 > putTextToHandle handle showProgress = PutText put initCnt
 >  where
 >   initCnt = if showProgress then 0 else -1
->   put line pers (-1) = do when pers (hPutStrLn handle line); return (-1)
+>   put line pers  cnt | cnt == (-1)
+>                      = do when pers (hPutStrLn handle line); return (-1)
 >   put line True  cnt = do hPutStrLn handle (erase cnt ++ line); return 0
 >   put line False cnt = do hPutStr handle ('\r' : line); return (length line)
 >     -- The "erasing" strategy with a single '\r' relies on the fact that the

</paste>
-- 
Shae Matijs Erisson - http://www.webwitches.com/~shae/
<radix> shapr: I think you *are* a purist :)
<radix> shapr: it's just that you're morally against unstable software, instead
        of morally against MS, or non-free software, or whatnot.