Make test helpers work for deferred routes

lib/devise/mapping.rb

@@ -33,7 +33,9 @@ class Mapping #:nodoc:
     # Receives an object and finds a scope for it. If a scope cannot be found,
     # raises an error. If a symbol is given, it's considered to be the scope.
     def self.find_scope!(obj)
+      Rails.application.routes_reloader.try(:execute_unless_loaded)
       obj = obj.devise_scope if obj.respond_to?(:devise_scope)
+
       case obj
       when String, Symbol
         return obj.to_sym