| Test::Warn - Perl extension to test methods for warnings |
Test::Warn - Perl extension to test methods for warnings
use Test::Warn;
warning_is {foo(-dri => "/")} "Unknown Parameter 'dri'", "dri != dir gives warning";
warnings_are {bar(1,1)} ["Width very small", "Height very small"];
warning_is {add(2,2)} undef, "No warning to calc 2+2"; # or
warnings_are {add(2,2)} [], "No warning to calc 2+2"; # what reads better :-)
warning_like {foo(-dri => "/"} qr/unknown param/i, "an unknown parameter test";
warnings_like {bar(1,1)} [qr/width.*small/i, qr/height.*small/i];
warning_is {foo()} {carped => 'didn't found the right parameters'};
warnings_like {foo()} [qr/undefined/,qr/undefined/,{carped => qr/no result/i}];
warning_like {foo(undef)} 'uninitialized';
warning_like {bar(file => '/etc/passwd')} 'io';
warning_like {eval q/"$x"; $x;/}
[qw/void uninitialized/],
"some warnings at compile time";
This module provides a few convenience methods for testing warning based code.
If you are not already familiar with the Test::More manpage now would be the time to go take a look.
warnings_are {foo()} [], "no warnings in".
If you want to test for a warning given by carp,
You have to write something like:
warning_is {carp "msg"} {carped = 'msg'}, ``Test for a carped warning''>.
The test will fail,
if a ``normal'' warning is found instead of a ``carped'' one.
Note: warn "foo" would print something like foo at -e line 1.
This method ignores everything after the at. That means, to match this warning
you would have to call warning_is {warn "foo"} "foo", "Foo succeeded".
If you need to test for a warning at an exactly line,
try better something like warning_like {warn "foo"} qr/at XYZ.dat line 5/.
warning_is and warning_are are only aliases to the same method.
So you also could write
warning_is {foo()} [], "no warning" or something similar.
I decided me to give two methods to have some better readable method names.
A true value is returned if the test succeeds, false otherwise.
The test name is optional, but recommended.
Please read also the notes to warning_is as these methods are only aliases.
If you want more than one tests for carped warnings look that way:
warnings_are {carp "c1"; carp "c2"} {carped = ['c1','c2'];> or
warnings_are {foo()} ["Warning 1", {carped = [``Carp 1'', ``Carp 2'']}, ``Warning 2'']>.
Note that {carped = ...}> has always to be a hash ref.
The REGEXP is matched after the whole warn line,
which consists in general of ``WARNING at __FILE__ line __LINE__''.
So you can check for a warning in at File Foo.pm line 5 with
warning_like {bar()} qr/at Foo.pm line 5/, "Testname".
I don't know whether it's sensful to do such a test :-(
However, you should be prepared as a matching with 'at', 'file', '\d'
or similar will always pass.
Think to the qr/^foo/ if you want to test for warning ``foo something'' in file foo.pl.
You can also write the regexp in a string as ``/.../'' instead of using the qr/.../ syntax. Note that the slashes are important in the string, as strings without slashes are reserved for warning categories (to match warning categories as can be seen in the perllexwarn man page).
Similar to warning_is,
you can test for warnings via carp with:
warning_like {bar()} {carped = qr/bar called too early/i};>
Similar to warning_is/warnings_are,
warning_like and warnings_like are only aliases to the same methods.
A true value is returned if the test succeeds, false otherwise.
The test name is optional, but recommended.
$Test::Warn::Categorization::tree,
allthough I wouldn't recommend it)
Thanks to the grouping in a tree, it's simple possible to test for an 'io' warning, instead for testing for a 'closed|exec|layer|newline|pipe|unopened' warning.
Note, that warnings occuring at compile time, can only be catched in an eval block. So
warning_like {eval q/"$x"; $x;/}
[qw/void uninitialized/],
"some warnings at compile time";
will work,
while it wouldn't work without the eval.
Note, that it isn't possible yet, to test for own categories, created with warnings::register.
Please read also the notes to warning_like as these methods are only aliases.
Similar to warnings_are,
you can test for multiple warnings via carp
and for warning categories, too:
warnings_like {foo()}
[qr/bar warning/,
qr/bar warning/,
{carped => qr/bar warning/i},
'io'
],
"I hope, you'll never have to write a test for so many warnings :-)";
warning_is,
warnings_are,
warning_like,
warnings_like by default.
Please note that warnings with newlines inside are making a lot of trouble.
The only sensful way to handle them is to use are the warning_like or
warnings_like methods. Background for these problems is that there is no
really secure way to distinguish between warnings with newlines and a tracing
stacktrace.
If a method has it's own warn handler,
overwriting $SIG{__WARN__},
my test warning methods won't get these warnings.
The warning_like BLOCK CATEGORY, TEST_NAME method isn't extremely tested.
Please use this calling style with higher attention and
tell me if you find a bug.
Improve this documentation.
The code has some parts doubled - especially in the test scripts. This is really awkward and has to be changed.
Please feel free to suggest me any improvements.
Have a look to the similar the Test::Exception manpage module.
Many thanks to Adrian Howard, chromatic and Michael G. Schwern, who have given me a lot of ideas.
Janek Schleicher, <bigj@kamelfreund.de>
Copyright 2002 by Janek Schleicher
This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
| Test::Warn - Perl extension to test methods for warnings |