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App::Cmd::Tester::CaptureExternal(3) User Contributed Perl Documentation App::Cmd::Tester::CaptureExternal(3)


App::Cmd::Tester::CaptureExternal - Extends App::Cmd::Tester to capture from external subprograms


version 0.336


  use Test::More tests => 4;
  use App::Cmd::Tester::CaptureExternal;
  use YourApp;
  my $result = test_app(YourApp => [ qw(command --opt value) ]);
  like($result->stdout, qr/expected output/, 'printed what we expected');
  is($result->stderr, '', 'nothing sent to sderr');
  ok($result->output, "STDOUT concatenated with STDERR");


App::Cmd::Tester provides a useful scaffold for testing applications, but it is unable to capture output generated from any external subprograms that are invoked from the application.

This subclass uses an alternate mechanism for capturing output (Capture::Tiny) that does capture from external programs, with one major limitation.

It is not possible to capture externally from both STDOUT and STDERR while also having appropriately interleaved combined output. Therefore, the "output" from this subclass simply concatenates the two.

You can still use "output" for testing if there is any output at all or for testing if something appeared in either output stream, but you can't rely on the ordering being correct between lines to STDOUT and lines to STDERR.


This library should run on perls released even a long time ago. It should work on any version of perl released in the last five years.

Although it may work on older versions of perl, no guarantee is made that the minimum required version will not be increased. The version may be increased for any reason, and there is no promise that patches will be accepted to lower the minimum required perl.


Ricardo Signes <>


This software is copyright (c) 2023 by Ricardo Signes.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

2024-03-08 perl v5.38.2