=head1 NAME

Test::Builder::Clutch - add a clutch to your testing drivechain

=head1 VERSION

Version 0.07

=head1 SYNOPSIS

   use Test::Builder::Clutch;

   # suspend test output
   Test::Builder::Clutch::disengage;

   # enable test output again
   Test::Builder::Clutch::engage;

   # is the clutch engaged?
   Test::Builder::Clutch::engaged ? 'yes' : 'no';
   Test::Builder::Clutch::disengaged ? 'no' : 'yes';

   # metaprogram non-test "foo" from "foo_ok"
   Test::Builder::Clutch::antitest qw/foo_ok/;

   # metaprogram non-test "is_bar" from "bar_ok"
   Test::Builder::Clutch::antitest { 'bar_ok' => 'is_bar' };


=head1 DESCRIPTION

Perhaps you have a test that does some useful work in its own right,
but you don't want to see all the test output when it's used outside
a testing context.  Rather than writing two subroutines - one that
emits TAP and one that doesn't - you can install
C<Test::Builder::Clutch> to turn the TAP on and off at will.

Routines are provided for engaging, disengaging in querying the state
of the clutch, and for metaprogramming non-test variants of test
routines..

=head1 L<Test::Builder> augmentations

C<Test::Builder::Clutch> adds an attribute named C<disengaged> to
L<Test::Builder>, as well as C<disengage> and C<engage> methods.

The C<disengaged> attribute actually cannot be initialised, since the
singleton Test::Builder is created when Test::Builder is loaded.  This is
the reason the attribute is called C<disengaged> rather than C<engaged>;
the "default" is necessarily undefined, and test output must remain
enabled when C<Test::Builder::Clutch> is loaded.

   $Test->disengaged(1);  # suspend test output
   $Test->disengaged(0);  # enable test output

   $Test->disengage;  # suspend test output
   $Test->engage;     # enable test output

=head2   ok

The original ok method is only invoked if the clutch in engaged, but the
C<is_passing> attribute is still set according the first argument.

=head2   child

The child Builder's clutch must be disengaged if the parent (that is, the
invocant) is disengaged; this wrapper takes care of that.

=head2   is_passing

If the clutch is currently engaged, defer to the original method.
If the clutch is disengaged, the test is considered to be passing
only if the original method returns true and no tests failed while
the clutch was disengaged.

=head1 SUBROUTINES

=head2   engaged

Return true if the clutch is currently engaged, otherwise false.

=head2   disengaged

Return true if the clutch is currently disengaged, otherwise false.

=head2   disengage

Disable test output.

=head2   engage

Enable test output.

=head2   antitest

Metaprogram non-test versions of test methods in the calling
package.

The argument is a list of strings and hash references.  Simple
strings must refer to an existing method whose name ends with "_ok".
The non-test methods' names will have the "_ok" stripped.

Hashref arguments give test method names as keys, and the desired
names of the corresponding non-test methods as values.

If the resultant non-test methods are called from within the
pacakge, the C<antitest> call must be executed in a C<BEGIN> block.

=head1 AUTHOR

Fraser Tweedale, C<< <frase at frase.id.au> >>


=head1 BUGS

Please report any bugs or feature requests to C<bug-test-clutch at rt.cpan.org>, or through
the web interface at L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Test-Builder-Clutch>.  I will be notified, and then you'll
automatically be notified of progress on your bug as I make changes.


=head1 SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Test::Builder::Clutch


You can also look for information at:

=over 4

=item * RT: CPAN's request tracker

L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Test-Builder-Clutch>

=item * AnnoCPAN: Annotated CPAN documentation

L<http://annocpan.org/dist/Test-Builder-Clutch>

=item * CPAN Ratings

L<http://cpanratings.perl.org/d/Test-Builder-Clutch>

=item * Search CPAN

L<http://search.cpan.org/dist/Test-Builder-Clutch/>

=back


=head1 SEE ALSO

L<Test::Builder> provides the test features that can be enabled/disabled
courtesy of this module.

L<Class::MOP> is the amazing meta-object protocol that makes all of this
possible.


=head1 LICENSE AND COPYRIGHT

Copyright 2011 Benon Technologies Pty Ltd
Copyright 2012 Fraser Tweedale

This program is free software; you can redistribute it and/or modify it
under the terms of either: the GNU General Public License as published
by the Free Software Foundation; or the Artistic License.

See http://dev.perl.org/licenses/ for more information.