private function getRelativePath(\SimpleXMLElement $fileName)
    {
        $dirOfSrcFiles = $this->element->project->directory["name"];
        $projectRoot = $this->rootDir;
        // Need to cut off everything lower than projectRoot
        $dirFromProjectRoot = substr($dirOfSrcFiles, strlen($projectRoot) + 1);
        // remove .xml and convert to string
        $relativeFilePath = substr((string)$fileName, 0, -4);
        return join(DIRECTORY_SEPARATOR, array($dirFromProjectRoot, $relativeFilePath));
    }