Unit Tests - bug_sort

- Added a unit test to cover the bug whereby certain combinations
  of adding tasks causes Table::sort to loop indefinitely.

src/tests/bug_sort.t

@@ -0,0 +1,62 @@
+#! /usr/bin/perl
+################################################################################
+## task - a command line task list manager.
+##
+## Copyright 2006 - 2009, Paul Beckingham.
+## All rights reserved.
+##
+## This program is free software; you can redistribute it and/or modify it under
+## the terms of the GNU General Public License as published by the Free Software
+## Foundation; either version 2 of the License, or (at your option) any later
+## version.
+##
+## This program is distributed in the hope that it will be useful, but WITHOUT
+## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+## FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+## details.
+##
+## You should have received a copy of the GNU General Public License along with
+## this program; if not, write to the
+##
+##     Free Software Foundation, Inc.,
+##     51 Franklin Street, Fifth Floor,
+##     Boston, MA
+##     02110-1301
+##     USA
+##
+################################################################################
+
+use strict;
+use warnings;
+use Test::More tests => 5;
+
+# Create the rc file.
+if (open my $fh, '>', 'bug_sort.rc')
+{
+  print $fh "data.location=.\n";
+  close $fh;
+  ok (-r 'bug_sort.rc', 'Created bug_sort.rc');
+}
+
+my $setup = "../task rc:bug_sort.rc add one;"
+          . "../task rc:bug_sort.rc add two;"
+          . "../task rc:bug_sort.rc add three recur:daily due:eom;";
+qx{$setup};
+
+my $output = qx{../task rc:bug_sort.rc list};
+#diag ($output);
+like ($output, qr/three.*(?:one.*two|two.*one)/msi, 'list did not hang');
+
+qx{../task rc:bug_sort.rc 1 priority:H};
+$output = qx{../task rc:bug_sort.rc list};
+like ($output, qr/three.*one.*two/msi, 'list did not hang after pri:H on 1');
+
+# Cleanup.
+unlink 'pending.data';
+ok (!-r 'pendind.data', 'Removed pending.data');
+
+unlink 'bug_sort.rc';
+ok (!-r 'bug_sort.rc', 'Removed bug_sort.rc');
+
+exit 0;
+