public static function setup($rootDirName = 'root', $permissions = null)
{
self::$root = vfsStream::newDirectory($rootDirName, $permissions);
if (true === self::$registered) {
return self::$root;
}
if (@stream_wrapper_register(vfsStream::SCHEME, __CLASS__) === false) {
throw new vfsStreamException('A handler has already been registered for the ' . vfsStream::SCHEME . ' protocol.');
}
self::$registered = true;
return self::$root;
}