There were actually 2 problems with this one:
* script_name was added to options as a string and then it was used
  in RouteSet#url_for with usage of <<, which was changing the original
  script_name
* the second issue was with _with_routes method. It was called in RoutesProxy
  to modify _routes in view_context, but url_helpers in views is just delegating
  it to controller, so another _with_routes call is needed there