diff --git a/lib/tests/backup_test.php b/lib/tests/backup_test.php
new file mode 100644
index 0000000000000..1830f56dce0ba
--- /dev/null
+++ b/lib/tests/backup_test.php
@@ -0,0 +1,184 @@
+<?php
+// This file is part of Moodle - http://moodle.org/
+//
+// Moodle 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 3 of the License, or
+// (at your option) any later version.
+//
+// Moodle 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 Moodle.  If not, see <http://www.gnu.org/licenses/>.
+
+/**
+ * Unit tests for backups.
+ *
+ * @package   core
+ * @category  phpunit
+ * @copyright 2012 Frédéric Massart <fred@moodle.com>
+ * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ */
+
+defined('MOODLE_INTERNAL') || die();
+
+global $CFG;
+require_once($CFG->dirroot . '/backup/util/helper/backup_cron_helper.class.php');
+
+/**
+ * Unit tests for backup system
+ */
+class backup_testcase extends advanced_testcase {
+
+    public function test_next_automated_backup() {
+
+        $this->resetAfterTest();
+        $admin = get_admin();
+        $timezone = $admin->timezone;
+
+        // Notes
+        // - The next automated backup will never be on the same date than $now
+        // - backup_auto_weekdays starts on Sunday
+        // - Tests cannot be done in the past.
+
+        // Every Wed and Sat at 11pm.
+        set_config('backup_auto_active', '1', 'backup');
+        set_config('backup_auto_weekdays', '0010010', 'backup');
+        set_config('backup_auto_hour', '23', 'backup');
+        set_config('backup_auto_minute', '0', 'backup');
+
+        $now = strtotime('next Monday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('2-23:00', date('w-H:i', $next));
+
+        $now = strtotime('next Tuesday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('5-23:00', date('w-H:i', $next));
+
+        $now = strtotime('next Wednesday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('5-23:00', date('w-H:i', $next));
+
+        $now = strtotime('next Thursday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('5-23:00', date('w-H:i', $next));
+
+        $now = strtotime('next Friday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('2-23:00', date('w-H:i', $next));
+
+        $now = strtotime('next Saturday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('2-23:00', date('w-H:i', $next));
+
+        $now = strtotime('next Sunday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('2-23:00', date('w-H:i', $next));
+
+        // Every Sun and Sat at 12pm.
+        set_config('backup_auto_active', '1', 'backup');
+        set_config('backup_auto_weekdays', '1000001', 'backup');
+        set_config('backup_auto_hour', '0', 'backup');
+        set_config('backup_auto_minute', '0', 'backup');
+
+        $now = strtotime('next Monday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('6-00:00', date('w-H:i', $next));
+
+        $now = strtotime('next Tuesday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('6-00:00', date('w-H:i', $next));
+
+        $now = strtotime('next Wednesday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('6-00:00', date('w-H:i', $next));
+
+        $now = strtotime('next Thursday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('6-00:00', date('w-H:i', $next));
+
+        $now = strtotime('next Friday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('6-00:00', date('w-H:i', $next));
+
+        $now = strtotime('next Saturday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-00:00', date('w-H:i', $next));
+
+        $now = strtotime('next Sunday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('6-00:00', date('w-H:i', $next));
+
+        // Every Sun at 4am.
+        set_config('backup_auto_active', '1', 'backup');
+        set_config('backup_auto_weekdays', '1000000', 'backup');
+        set_config('backup_auto_hour', '4', 'backup');
+        set_config('backup_auto_minute', '0', 'backup');
+
+        $now = strtotime('next Monday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-04:00', date('w-H:i', $next));
+
+        $now = strtotime('next Tuesday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-04:00', date('w-H:i', $next));
+
+        $now = strtotime('next Wednesday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-04:00', date('w-H:i', $next));
+
+        $now = strtotime('next Thursday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-04:00', date('w-H:i', $next));
+
+        $now = strtotime('next Friday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-04:00', date('w-H:i', $next));
+
+        $now = strtotime('next Saturday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-04:00', date('w-H:i', $next));
+
+        $now = strtotime('next Sunday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-04:00', date('w-H:i', $next));
+
+        // Every day but Wed at 8:30pm.
+        set_config('backup_auto_active', '1', 'backup');
+        set_config('backup_auto_weekdays', '1110111', 'backup');
+        set_config('backup_auto_hour', '20', 'backup');
+        set_config('backup_auto_minute', '30', 'backup');
+
+        $now = strtotime('next Monday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('2-20:30', date('w-H:i', $next));
+
+        $now = strtotime('next Tuesday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('4-20:30', date('w-H:i', $next));
+
+        $now = strtotime('next Wednesday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('4-20:30', date('w-H:i', $next));
+
+        $now = strtotime('next Thursday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('5-20:30', date('w-H:i', $next));
+
+        $now = strtotime('next Friday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('6-20:30', date('w-H:i', $next));
+
+        $now = strtotime('next Saturday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('0-20:30', date('w-H:i', $next));
+
+        $now = strtotime('next Sunday');
+        $next = backup_cron_automated_helper::calculate_next_automated_backup($timezone, $now);
+        $this->assertEquals('1-20:30', date('w-H:i', $next));
+
+    }
+}