/**
  * Creates the filebase by options
  */
 public function setUp()
 {
     if (!($filebase_id = $this->getOption('filebase', null))) {
         throw new sfFilebasePluginException('You must specify a filebase to use this behaviour');
     }
     $this->filebase = sfFilebasePlugin::getInstance($filebase_id);
     if (!$this->filebase->fileExists()) {
         throw new sfFilebasePluginException('The filebase directory does not exist.');
     }
 }