This will make sure the application will raise `ActionController::RoutingError` in case "X-Cascade: pass" header was set, usually when there's no route match.

This has been used by `show_exception` middleware even the setting wasn't get passed to `env` hash.

observers leak across tests, so rather than modify the object, we should just count the number of times the observer was called

Signed-off-by: NJosé Valim <jose.valim@gmail.com>

Signed-off-by: NSantiago Pastorino <santiago@wyeworks.com>

Relation will delegate to AR::Base which already uses the Dynamic finders, so eliminate duplicate calls