7 utilities for improving application quality in Perl

I’d like to share with you a list of what are probably my top utilities for improving code quality (style, documentation, testing) with a largely Perl flavour. In loosely important-but-dull to exciting-and-weird order…

Test::More. Billed as yet another framework for writing test scripts Test::More extends Test::Simple and provides a bunch of more useful methods beyond Simple’s ok(). The ones I use most being use_ok() for testing compilation, is() for testing equality and like() for testing similarity with regexes.

ExtUtils::MakeMaker. Another one of Mike Schwern’s babies, MakeMaker is used to set up a folder structure and associated ‘make’ paraphernalia when first embarking on writing a module or application. Although developers these days tend to favour Module::Build over MakeMaker I prefer it for some reason (probably fear of change) and still make regular mileage using it.

Test::Pod::Coverage – what a great module! Check how good your documentation coverage is with respect to the code. No just a subroutine header won’t do! I tend to use Test::Pod::Coverage as part of…

Test::Distribution . Automatically run a battery of standard tests including pod coverage, manifest integrity, straight compilation and a load of other important things.

perlcritic, Test::Perl::Critic . The Perl::Critic set of tools is amazing. It’s built on PPI and implements the Perl Best Practices book by Damien Conway. Now I realise that not everyone agrees with a lot of what Damien says but the point is that it represents a standard to work to (and it’s not that bad once you’re used to it). Since I discovered perlcritic I’ve been developing all my code as close to perlcritic -1 (the most severe) as I can. It’s almost instantly made my applications more readable through systematic appearance and made faults easier to spot even before Test::Perl::Critic comes in.

Devel::Cover. I’m almost ashamed to say I only discovered this last week after dipping into Ian Langworthy and chromatic’s book ‘Perl Testing’. Devel::Cover gives code exercise metrics, i.e. how much of your module or application was actually executed by that test. It collates stats from all modules matching a user-specified pattern and dumps them out in a natty coloured table, very suitable for tying into your CI system.

Selenium . Ok, not strictly speaking a tool I’m using right this minute but it’s next on my list of integration tools. Selenium is a non-interactive, automated, browser-testing framework written in Javascript. This tool definitely has legs and it seems to have come a long way since I first found it in the middle of 2006. I’m hoping to have automated interface testing up and running before the end of the year as part of the Perl CI system I’m planning on putting together for the new sequencing pipeline.