Assuming your module takes over STDERR, and then relies on the behavior of croak (or, really, die) to write to STDERR, I don't think you'll get your tests to work with eval, which supresses the write to STDERR. You may be better off using a signal handler: 

local $SIG{__DIE__} = sub { 
  local $|++; # autoflush
  print STDERR @_; 
};

unlink 'test.errors';

redirect_error( output_file => 'test.errors' ); 

# call this directly, not in an eval, as you're trapping the croak
lcroak "this is a sample error file";

ok( -T 'test.errors',
    "lcroak opens the error file specified by redirect_error()." );

my $text = `cat test.errors`;
like( $text , qr/this is a sample error file/,
    "lcroak writes to the error file specified by redirect_error()." )
+;

unlink 'test.errors';

[download]

Picking a nit -- cat test.errors isn't portable. You may want to use File::Slurp or the equivalent and keep it in Perl.

Also, if you want to do this test by running a separate process, I'd suggest trying IPC::Run3 instead of using a system call. It will nicely redirect STDOUT and STDERR into scalar variables for you:

run3 \@cmd, undef, \$out, \$err;

[download]

-xdg

Code written by xdg and posted on PerlMonks is public domain. It is provided as is with no warranties, express or implied, of any kind. Posted code may not have been tested. Use of posted code is at your own risk.

In reply to Re: Testing redirected croak messages by xdg
in thread Testing redirected croak messages by macrobat

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.