/**
  * Set default Purifier
  *
  * @param HtmlPurifier $purifier
  */
 public static function setDefaultPurifier(HtmlPurifier $purifier = null)
 {
     self::$_defaultPurifier = $purifier;
 }
 /**
  * @covers Robo47_Filter_HtmlPurifier::setPurifier
  * @covers Robo47_Filter_HtmlPurifier::_purifierFromRegistry
  * @covers Robo47_Filter_Exception
  */
 public function testSetPurifierFromRegistryWithoutPurifierinRegistry()
 {
     $filter = new Robo47_Filter_HtmlPurifier();
     try {
         $filter->setPurifier('MyPurifier');
         $this->fail('No exception thrown on setting purifier via registry without existing in Registry');
     } catch (Robo47_Filter_Exception $e) {
         $this->assertEquals('Registry key "MyPurifier" for HtmlPurifier is not registered.', $e->getMessage(), 'Wrong Exception Message');
     }
 }