When the kernel is booted in different unit test the followin exception is thrown.
ErrorException: Warning: stream_wrapper_register(): Protocol s3:// is already defined. in vendor/pear/Services/Amazon/S3/Stream.php line 276
This can be fixed by adding a shutdown method in the class OrchestraS3StreamBundle
/**
* Shutdowns the Bundle.
*/
public function shutdown()
{
stream_wrapper_unregister('s3');
parent::shutdown();
}