function formatValue($field, $value)
 {
     switch ($field) {
         case self::ADD_ATTACHMENT:
             $attachFileCommandLink = $this->command->getAttachFileCommandLink($this->currentFileName);
             return $attachFileCommandLink;
             break;
         default:
             return parent::formatValue($field, $value);
     }
 }
 /**
  * @expectedException MWException
  * @expectedExceptionMessage invalid_field
  * @covers ImageListPager::formatValue
  */
 public function testFormatValuesThrowException()
 {
     $page = new ImageListPager(RequestContext::getMain());
     $page->formatValue('invalid_field', 'invalid_value');
 }