Comment 1 for bug 1363060

Actually it doesn't look like a bug. API did what you've asked - filtered backups by instance id that doesn't exist. But i do agree, that we need to raise HTTP 404 Not Found for cases like this.

I've noticed that we didn't filtering by instance ID at all,
see https://github.com/openstack/python-troveclient/blob/master/troveclient/v1/backups.py#L41-L51
and see https://github.com/openstack/trove/blob/master/trove/backup/service.py#L35-L46