/**
  * Opens the csv and make assertions.
  *
  * @param String 	$filePath
  *
  * @return resource
  **/
 private function assertOpenCSV($filePath)
 {
     $filePointer = CSVFileService::getFilePointer($filePath);
     $this->assertNotNull($filePointer);
     $this->assertInternalType('resource', $filePointer);
     return $filePointer;
 }