function testCannotSaveWithInvertedInterval()
 {
     try {
         $expected_record = array('uid' => $this->expected_uid, 'jobid' => $this->expected_jobid, 'start_time' => 1308829978, 'end_time' => 1308825379);
         $mapping = new TZUserJobMapping($expected_record);
         $mapping->setDBWrapper($this->dbWrapper);
         $mapping->save();
         $this->fail('should have received validation exception');
     } catch (TZDBValidationException $e) {
         $expected_errors = array(t('Inverted interval'));
         $this->assertEquals($expected_errors, $e->getErrors());
     }
 }