Test::Perl::Critic::Policy(3pm)

NAME
Test::Perl::Critic::Policy - A framework for testing your custom Policies

SYNOPSIS
    use Test::Perl::Critic::Policy qw< all_policies_ok >;

    # Assuming .run files are inside 't' directory...
    all_policies_ok()

    # Or if your .run files are in a different directory...
    all_policies_ok( '-test-directory' => 'run' );

    # And if you just want to run tests for some polices...
    all_policies_ok( -policies => ['Some::Policy', 'Another::Policy'] );

    # If you want your test program to accept short Policy names as
    # command-line parameters...
    #
    # You can then test a single policy by running
    # "perl -Ilib t/policy-test.t My::Policy".
    my %args = @ARGV ? ( -policies => [ @ARGV ] ) : ();
    all_policies_ok(%args);

DESCRIPTION
This module provides a framework for function-testing your custom Perl::Critic::Policy modules. Policy testing usually involves feeding it a string of Perl code and checking its behavior. In the old days, those strings of Perl code were mixed directly in the test script. That sucked.

IMPORTABLE SUBROUTINES

all_policies_ok('-test-directory' => $path, -policies => \@policy_names)
    Loads all the *.run files beneath the "-test-directory" and runs the tests. If "-test-directory" is not specified, it defaults to t/. "-policies" is an optional reference to an array of shortened Policy names. If "-policies" specified, only the tests for Policies that match one of the "m/$POLICY_NAME/imx" will be run.

CREATING THE *.run FILES
Testing a policy follows a very simple pattern:

    * Policy name
        * Subtest name
        * Optional parameters
        * Number of failures expected
        * Optional exception expected
        * Optional filename for code

Each of the subtests for a policy is collected in a single .run file, with test properties as comments in front of each code block that describes how we expect Perl::Critic to react to the code. For example, say you have a policy called Variables::ProhibitVowels:

    (In file t/Variables/ProhibitVowels.run)

    ## name Basics
    ## failures 1
    ## cut

    my $vrbl_nm = 'foo';    # Good, vowel-free name
    my $wango = 12;         # Bad, pronouncable name

    ## name Sometimes Y
    ## failures 1
    ## cut

    my $yllw = 0;       # "y" not a vowel here
    my $rhythm = 12;    # But here it is

These are called "subtests", and two are shown above. The beauty of incorporating multiple subtests in a file is that the .run is itself a (mostly) valid Perl file, and not hidden in a HEREDOC, so your editor's color-coding still works, and it is much easier to work with the code and the POD.

If you need to pass any configuration parameters for your subtest, do so like this:

    ## parms { allow_y => '0' }

Note that all the values in this hash must be strings because that's what Perl::Critic will hand you from a .perlcriticrc.

If it's a TODO subtest (probably because of some weird corner of PPI that we exercised that Adam is getting around to fixing, right?), then make a "##TODO" entry.

    ## TODO Should pass when PPI 1.xxx comes out

If the code is expected to trigger an exception in the policy, indicate that like so:

    ## error 1

If you want to test the error message, mark it with "/.../" to indicate a like() test:

    ## error /Can't load Foo::Bar/

If the policy you are testing cares about the filename of the code, you can indicate that "fcritique" should be used like so (see "fcritique" for more details):

    ## filename lib/Foo/Bar.pm

The value of "parms" will get "eval"ed and passed to pcritique(), so be careful.

In general, a subtest document runs from the "## cut" that starts it to either the next "## name" or the end of the file. In very rare circumstances you may need to end the test document earlier. A second "## cut" will do this. The only known need for this is in t/Miscellanea/RequireRcsKeywords.run, where it is used to prevent the RCS keywords in the file footer from producing false positives or negatives in the last test.

Note that nowhere within the .run file itself do you specify the policy that you're testing. That's implicit within the filename.

BUGS AND CAVEATS AND TODO ITEMS
Add policy_ok() method for running subtests in just a single TODO file.

Can users mark this entire test as TODO or SKIP, using the normal mechanisms?

Allow us to specify the nature of the failures, and which one. If there are 15 lines of code, and six of them fail, how do we know they're the right six?

Consolidate code from Perl::Critic::TestUtils and possibly deprecate some functions there.

Write unit tests for this module.

Test that we have a t/*/*.run for each lib/*/*.pm

AUTHOR
Andy Lester, Jeffrey Ryan Thalhammer <thaljef@cpan.org>

COPYRIGHT
Copyright (c) 2009-2023 Andy Lester

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. The full text of this license can be found in the LICENSE file included with this module.