Testing a module's stdout/stderr

pileofrogs has asked for the wisdom of the Perl Monks concerning the following question:

I'm writing a convenience module that makes it easy to add debugging output to quick scripts. I'd like to make some tests ala Test::More and I'm wondering what's the best way to test based on the printed or warned output from a module?

Can I do something like E.G.:

grab_stdout($foo);
print 'gabba gabba hey';
ungrab_stdout();
ok($foo eq 'gabba gabba hey`) 
  || diag "didn't print 'gabba gabba hey' to stdout.";
[download]

... or something similer... possibly better....?

Basically, I want to test if the stuff I wanted to send to stdout/stderr did in fact go to stout/stderr.

Thanks!
-Pileofrogs

Comment on Testing a module's stdout/stderr Download Code

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Re: Testing a module's stdout/stderr by Old_Gray_Bear (Bishop) on Mar 24, 2007 at 00:57 UTC
Take a look at Perl Testing - A Developer's Notebook; Langworth and chromatic. Page 105-106 has a discussion of how to build tests for your STDERR output. ---- I Go Back to Sleep, Now. OGB	[reply]
Re: Testing a module's stdout/stderr by kyle (Abbot) on Mar 24, 2007 at 00:56 UTC
It doesn't follow the syntax example you have, but maybe Test::Output could do what you want.	[reply]
Re: Testing a module's stdout/stderr by grinder (Bishop) on Mar 24, 2007 at 09:59 UTC
To test STDERR (that is, stuff that warn emits, as well as direct prints to STDERR), you can use Test::Warning. I use this for a couple of distributions, and it's great. Hmm... I didn't know about cpan:://Test::Output, which should solve both problems. Just goes to show, you can test just about anything these days. • another intruder with the mooring in the heart of the Perl	[reply]
Re: Testing a module's stdout/stderr by Sidhekin (Priest) on Mar 24, 2007 at 12:01 UTC
... or you could use my Test::Trap. :) `use Test::More tests => 1; use Test::Trap; trap { print 'gabba gabba hey'; }; ok($trap->stdout eq 'gabba gabba hey') \|\| diag "didn't print 'gabba gabba hey' to stdout.";` [download] Edit: On second thought, `$trap->stdout_is('gabba gabba hey')` may be more than you want. The good news is that `->stdout`, as above, gives you all you were asking for. `print "Just another Perl ${\(trickster and hacker)},"` The Sidhekin proves Sidhe did it!	[reply] [d/l] [select]