NAME
Devel::Cover - Code coverage metrics for Perl
SYNOPSIS
perl -MDevel::Cover yourprog args
cover
perl -MDevel::Cover=-db,cover_db,-coverage,statement,time yourprog args
To test an uninstalled module:
cover -delete
HARNESS_PERL_SWITCHES=-MDevel::Cover make test
cover
If the module does not use the t/*.t framework:
PERL5OPT=-MDevel::Cover make test
DESCRIPTION
This module provides code coverage metrics for Perl.
If you can't guess by the version number this is an alpha release.
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.
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. 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
Perl 5.6.1 or greater
Perl 5.7.0 is unsupported. Perl 5.8.1 or greater is recommended. Whilst Perl 5.6 should work you will probably miss out on coverage information which would be available using a more modern version.
The ability to compile XS extensions.
This means a working compiler and make program at least.
Storable and Digest::MD5
Both are in the core in Perl 5.8.0 and above.
-
if you want Pod coverage.
-
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, 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)
-summary val - Print summary information iff val is true (default on).
SELECTING FILES TO COVER
You may select which files you want covered using the select, ignore and inc options. The system works as follows:
Any file matching a RE given as a select option is selected.
Otherwise, any file matching a RE given as an ignore option is ignored.
Otherwise, any file in one of the inc directories is ignored.
Otherwise the file is selected.
You may add to the REs to select by using +select, or you may reset the selections using -select. The same principle applies to the REs to ignore.
The inc directories are initially populated with the contects of the @INC array at the time Devel::Cover was built. You may reset these directories using -inc, or add to them using +inc.
ACKNOWLEDGEMENTS
Some code and ideas cribbed from:
Devel::OpProf
B::Concise
B::Deparse
SEE ALSO
Devel::Cover::Tutorial
B
Pod::Coverage
LIMITATIONS
There are things that Devel::Cover can't cover.
Absence of shared dependencies
Perl keeps track of which modules have been loaded (to avoid reloading them). Because of this, it isn't possible to get coverage for a path where a runtime import fails if the module being imported is one that Devel::Cover uses internally. For example, suppose your program has this function:
sub foo {
eval { require Storable };
if ($@) {
carp "Can't find Storable";
return;
}
# ...
}
You might write a test for the failure mode as
BEGIN { @INC = () }
foo();
# check for error message
Because Devel::Cover uses Storable internally, the import will succeed (and the test will fail) under a coverage run.
Modules used by Devel::Cover while gathering coverage:
B
B::Debug
B::Deparse
Carp
Cwd
Digest::MD5
File::Path
File::Spec
Storable
BUGS
Did I mention that this is alpha code?
See the BUGS file. And the TODO file.
VERSION
Version 0.44 - 18th May 2004
LICENCE
Copyright 2001-2004, Paul Johnson (pjcj@cpan.org)
This software is free. It is licensed under the same terms as Perl itself.
The latest version of this software should be available from my homepage: http://www.pjcj.net