Silence a warning in TAP

Question

My code has a test for a bad API call, fortunately that code results in a warning from the module itself. But when I'm testing the failed API call I want to not see the warning in TAP.

t/01-pass.t .............. ok
t/02-fail.t .............. ok
t/03-noversion.t ......... ok
t/04-no-file.t ........... ok
Use of uninitialized value $file in concatenation (.) or string at /home/xenoterracide/projects/Test-Version/lib/Test/Version.pm line 29.
t/05-file-not-defined.t .. ok
# unsorted oks: 001
t/06-all.t ............... ok
All tests successful.
Files=6, Tests=37,  1 wallclock secs ( 0.04 usr  0.02 sys +  0.35 cusr  0.04 csys =  0.45 CPU)
Result: PASS

Here's the actual code

#!/usr/bin/perl
use 5.006;
use strict;
use warnings;
use Test::Tester tests => 7;
use Test::Version qw( version_ok );

check_test(
    sub {
        version_ok; # correct call version_ok( $file )
    },
    {
        ok => 0,
        name => 'check version in ',
        diag => 'FILE_NOT_DEFINED',
    },
    '$file not defined'
);

is there any way to squelch the warning and prevent to prevent it from ending up in TAP (outside of no warnings in the original module).

Answer 1

You're possibly looking for Test::Warn. It's easy to use:

use strict;
use warnings;
use Test::More;
use Test::Warn;
# You might also find the following modules interesting:
# use Test::Exception;
# use Test::NoWarnings;

sub bla { warn 'bla' }

warning_is { bla() } 'bla';
done_testing;

So you're transforming the warning from a nuisance into something expected.

If this is not what you want, then take a look at IO::CaptureOutput or - de préférence, according to the author of both modules, David Golden - at Capture::Tiny.

You could also code everything by hand redirecting STDERR to buffer for the time you're making the call that'll emit the warning.