NAME Devel::Cover - Code coverage metrics for Perl SYNOPSIS To get coverage for an uninstalled module: cover -test or cover -delete HARNESS_PERL_SWITCHES=-MDevel::Cover make test cover To get coverage for an uninstalled module which uses Module::Build (0.26 or later): ./Build testcover If the module does not use the t/*.t framework: PERL5OPT=-MDevel::Cover make test If you want to get coverage for a program: perl -MDevel::Cover yourprog args cover perl -MDevel::Cover=-db,cover_db,-coverage,statement,time yourprog args DESCRIPTION This module provides code coverage metrics for Perl. Code coverage metrics describe how thoroughly tests exercise code. By using Devel::Cover you can discover areas of code not exercised by your tests and determine which tests to create to increase coverage. Code coverage can be considered as an indirect measure of quality. I consider this software to have an alpha status. By that I mean that I reserve the right to alter the interface in a backwards incompatible manner without incrementing the major version number. I specifically do not mean that this software is full of bugs or missing key features. Although I'm making no guarantees on that front either. In short, if you are looking for code coverage software for Perl, you have probably come to the end of your search. For more of my opinions on this subject, see http://pjcj.sytes.net/notes/2007/03/14#alpha Code coverage data are collected using a pluggable runops function which counts how many times each op is executed. These data are then mapped back to reality using the B compiler modules. There is also a statement profiling facility which needs a better backend to be really useful. This release also includes an experimental mode which replaces ops instead of using a pluggable runops function. This provides a nice speed increase, but needs better testing before it becomes the default. You probably don't care about any of this. The cover program can be used to generate coverage reports. Statement, branch, condition, subroutine, pod and time coverage information is reported. Statement coverage data should be reasonable, although there may be some statements which are not reported. Branch and condition coverage data should be mostly accurate too, although not always what one might initially expect. Subroutine coverage should be as accurate as statement coverage. Pod coverage comes from Pod::Coverage. If Pod::Coverage::CountParents is available it will be used instead. Coverage data for path coverage are not yet collected. The gcov2perl program can be used to convert gcov files to "Devel::Cover" databases. You may find that the results don't match your expectations. I would imagine that at least one of them is wrong. The most appropriate mailing list on which to discuss this module would be perl-qa. Discussion has migrated there from perl-qa-metrics which is now defunct. See . The Devel::Cover repository can be found at . REQUIREMENTS * Perl 5.6.1 or greater. Perl 5.8.8 or greater is recommended. Perl 5.7.0 is unsupported. Perl 5.8.8 or greater is recommended. Perl 5.8.7 has problems and may crash. Whilst Perl 5.6 should mostly work you will probably miss out on coverage information which would be available using a more modern version and will likely run into bugs in perl. Different versions of perl may give slightly different results due to changes in the op tree. * The ability to compile XS extensions. This means a working C compiler and make program at least. If you built perl from source you will have these already and they will be used automatically. If your perl was built in some other way, for example you may have installed it using your Operating System's packaging mechanism, you will need to ensure that the appropriate tools are installed. * Storable and Digest::MD5 Both are in the core in Perl 5.8.0 and above. * Template and PPI::HTML or Perl::Tidy if you want syntax highlighted HTML reports. * Pod::Coverage if you want Pod coverage. * Test::More in order to run the tests * Test::Warn in order to run some of the tests * Test::Differences if the tests fail and you would like nice output telling you why.