public function testNotSupportedEncoderResultThrowsException()
 {
     $instance = new DataItemToElementEncoder();
     $instance->registerDataItemEncoder(\SMWDataItem::TYPE_BLOB, function ($datatem) {
         return new \Stdclass();
     });
     $this->setExpectedException('RuntimeException');
     $instance->mapDataItemToElement(new \SMWDIBlob('foo'));
 }