=head1 NAME

Test::LectroTest::RegressionTesting - How to do regression testing (for free!)

=head1 SYNOPSIS

    use Test::LectroTest
        regressions => "regressions.txt";

    # -- OR --

    use Test::LectroTest
        playback_failures => "regression_suite_for_my_module.txt",
        record_failures   => "failures_in_the_field.txt";

    # -- OR --

    use Test::LectroTest::Compat
        regressions => "regressions.txt";

    # -- OR --

    use Test::LectroTest::Compat
        playback_failures => "regression_suite_for_my_module.txt",
        record_failures   => "failures_in_the_field.txt";


=head1 DESCRIPTION

Say that LectroTest uncovers a bug in your software by finding a
random test case that proves one of your properties to be false.  If
you apply a fix for the bug, how can you be sure that LectroTest will
re-test the property using the exact same test case that "broke" it
before, just to be certain the bug really is fixed?  And how can you
be sure that future changes to your code will not reintroduce the same
bug without your knowing it?

For situations like these, LectroTest can record failure-causing test
cases to a file, and it can play those test cases back as part of its
normal testing strategy.

The easiest way to take advantage of this feature is to set the
I<regressions> parameter when you C<use> L<Test::LectroTest>
or L<Test::LectroTest::Compat>:

    use Test::LectroTest
        regressions => "regressions.txt";

This tells LectroTest to use the file "regressions.txt" for both
recording and playing back failures.  If you want to record and
play back from separate files, use the I<record_failures> and
I<playback_failures> options:

    use Test::LectroTest::Compat
        playback_failures => "regression_suite_for_my_module.txt",
        record_failures   => "failures_in_the_field.txt";

Here is how it works:

=over 4

=item 1

When testing a property named I<N>, LectroTest will check for a
play-back file.  If the file exists, LectroTest will search it for
test cases associated with I<N>.  If any such test cases exist,
LectroTest will play them back I<before> and I<in addition to>
performing the usual, random testing of the property.

=item 2

When performing the usual, random testing of a property named I<N>,
if a failure occurs (i.e., LectroTest finds a counterexample),
LectroTest will record the test case that caused the failure to
the recording file, associating the test case with the name I<N>.

=back

B<NOTE:> If you pass any of the recording or playback parameters to
L<Test::LectroTest::Compat>, you must have version 0.3500 or greater
of Test::LectroTest installed.  (Module authors, update your modules'
build dependencies accordingly.)  The L<Test::LectroTest> module
itself, however, has always ignored unfamiliar parameters, and thus
these options are backward compatible with older versions.


=cut


=head1 SEE ALSO

L<Test::LectroTest> gives a quick overview of automatic,
specification-based testing with LectroTest.  This module
accepts failure recording and play-back options.

L<Test::LectroTest::Compat> lets you mix LectroTest with the
popular family of L<Test::Builder>-based modules such as
L<Test::Simple> and L<Test::More>. This module
accepts failure recording and play-back options.



=head1 LECTROTEST HOME

The LectroTest home is
http://community.moertel.com/LectroTest.
There you will find more documentation, presentations, mailing-list archives, a wiki,
and other helpful LectroTest-related resources.  It's also the
best place to ask questions.

=head1 AUTHOR

Tom Moertel (tom@moertel.com)

=head1 COPYRIGHT and LICENSE

Copyright (c) 2004-06 by Thomas G Moertel.  All rights reserved.

This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.

=cut
