Devel::Cover(3pm) - phpMan

Devel::Cover(3pm) User Contributed Perl Documentation Devel::Cover(3pm)

NAME
Devel::Cover - Code coverage metrics for Perl

SYNOPSIS
To get coverage for an uninstalled module:

cover -test

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
<http://lists.perl.org/showlist.cgi?name=perl-qa>.

REQUIREMENTS
o Perl 5.6.1 or greater. Perl 5.8.2 or greater is recommended.

Perl 5.7.0 is unsupported. Perl 5.8.2 or greater is recommended. 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. Perl
5.8.0 will give slightly different results to more recent versions due to changes in
the op tree.

o The ability to compile XS extensions.

This means a working compiler and make program at least.

o Storable and Digest::MD5

Both are in the core in Perl 5.8.0 and above.

o Template and PPI::HTML or Perl::Tidy

if you want syntax highlighted HTML reports.

o Pod::Coverage

if you want Pod coverage.

o Test::Differences

if the tests fail and you would like nice output telling you why.

OPTIONS
-blib - "use blib" and ignore files matching \bt/ (default true
iff blib directory exists).
-coverage criterion - Turn on coverage for the specified criterion. Criteria
include statement, branch, condition, path, subroutine,
pod, time, all and none (default all available).
-db cover_db - Store results in coverage db (default ./cover_db).
-dir path - Directory in which coverage will be collected (default
cwd).
-ignore RE - Set REs of files to ignore (default "/Devel/Cover\b").
+ignore RE - Append to REs of files to ignore.
-inc path - Set prefixes of files to ignore (default @INC).
+inc path - Append to prefixes of files to ignore.
-merge val - Merge databases, for multiple test benches (default on).
-select RE - Set REs of files to select (default none).
+select RE - Append to REs of files to select.
-silent val - Don't print informational messages (default off)
-subs_only val - Only cover code in subroutine bodies (default off)
-summary val - Print summary information iff val is true (default on).