Perl Test::More and setting up test requirements.

Question

With Test::More I often want to have a module that runs tests and has the ability to abort the callers test_plan. I have a series of tests that set up a plugin list for Catalyst::Test. I don't want to have to make my test check to see if they exist; instead, I want my script to abort if those plugins aren't present.

I was trying to track down a bug in my Catalyst::Authentication::Store::DBI::ButMaintained, and I noticed this bug is also present in Catalyst::Authentication::Store::DBI. Here it is:

eval {
  require Catalyst::Model::DBI;
  require Catalyst::Plugin::Session;
  require Catalyst::Plugin::Session::State::Cookie;
  require Catalyst::Plugin::Session::Store::File;
  require DBD::SQLite;
  require Test::WWW::Mechanize::Catalyst;
} or plan skip_all => $@;

...

$ENV{'TESTAPP_PLUGINS'} = [ qw(
  Authentication
  Session
  Session::Store::File
  Session::State::Cookie
  Authorization::Roles
) ];

As you can see, the eval/skip_all doesn't check Authorization::Roles inclusion, but the test depends on it by virtue of it being a plugin.

I have another question though -- is there a more elegant way to specify Test-dependencies than this? Keep in mind my goal is the same as the original authors. I simply want to skip the test, if the test requirements don't exist. Ideally, in this case, I'd like to hack Catalyst::Test to wrap the plugin mechanism for Catalyst::Plugin::* stuff, and then find a better way to do the rest of this stuff without eval/skip_all.

Answer 1

You can dynamically affect the # of tests in the plan by calling:

Test::More->builder->plan(tests=>$total_tests);

You can use that do conditionally calculate the # of tests based on the needs.

Answer 2

Update with your list of plugins as needed:

If you are testing a bunch of requirements in a separate package, you could simply have that package return false (rather than the traditional true value) if a dependency is not met:

package Catalyst::Test;

eval {
    use Dep1;
    use Dep2;
    # ...
}

# dep check package returns true if we found all the modules
!$@;

# test.pl
use Test::Requires {
    Catalyst::Test => 0.01,  # skip all tests if Catalyst::Test is not present
};
use Test::More tests => 20;  # call Test::More as normal.

When I run this using a dep checker called Foo, this fails with appropriate output:

% perl -I. foo.t
1..0 # SKIP Foo.pm did not return a true value at (eval 4) line 2.
# BEGIN failed--compilation aborted at (eval 4) line 2.
#

% prove -I. foo.t
foo.pl .. skipped: Foo.pm did not return a true value at (eval 4) line 2.
Files=1, Tests=0,  0 wallclock secs ( 0.02 usr  0.01 sys +  0.01 cusr  0.00 csys =  0.04 CPU)
Result: NOTESTS