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
To alter default values:
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 an indirect measure of quality.
Although it is still being developed, Devel::Cover is now quite stable
and provides many of the features to be expected in a useful coverage
tool.
Statement, branch, condition, subroutine, and pod coverage information
is reported. Statement and subroutine coverage data should be accurate.
Branch and condition coverage data should be mostly accurate too,
although not always what one might initially expect. Pod coverage comes
from Pod::Coverage. If Pod::Coverage::CountParents is available it will
be used instead. Coverage data for other criteria are not yet
collected.
The cover program can be used to generate coverage reports.
Devel::Cover ships with a number of different reports including various
types of HTML output, textual reports, a report to display missing
coverage in the same format as compilation errors and a report to
display coverage information within the Vim editor.
It is possible to add annotations to reports, for example you can add a
column to an HTML report showing who last changed a line, as determined
by git blame. Some annotation modules are shipped with Devel::Cover and
you can easily create your own.
The gcov2perl program can be used to convert gcov files to
"Devel::Cover" databases. This allows you to display your C or XS code
coverage together with your Perl coverage, or to use any of the
Devel::Cover reports to display your C coverage data.
Code coverage data are collected by replacing perl ops with functions
which count how many times the ops are executed. These data are then
mapped back to reality using the B compiler modules. There is also a
statement profiling facility which should not be relied on. For proper
profiling use Devel::NYTProf. Previous versions of Devel::Cover
collected coverage data by replacing perl's runops function. It is
still possible to switch to that mode of operation, but this now gets
little testing and will probably be removed soon. You probably don't
care about any of this.
The most appropriate mailing list on which to discuss this module would
be perl-qa. See <http://lists.perl.org/list/perl-qa.html>.
The Devel::Cover repository can be found at
<http://github.com/pjcj/Devel--Cover>. This is also where problems
should be reported.