Make engine check more explicit

Not everything that responds to `routes` is a Rails engine - for example
a Grape API endpoint will have a `routes` method but can't be used with
`assert_recognizes` as it doesn't respond to `recognize_path_with_request`.

Fixes #32312.

1 files changed, 9 insertions, 6 deletions

diff --git a/actionpack/lib/action_dispatch/routing/endpoint.rb b/actionpack/lib/action_dispatch/routing/endpoint.rb
index 24dced1efd..28bb20d688 100644
--- a/actionpack/lib/action_dispatch/routing/endpoint.rb
+++ b/actionpack/lib/action_dispatch/routing/endpoint.rb
@@ -3,12 +3,15 @@
 module ActionDispatch
   module Routing
     class Endpoint # :nodoc:
-      def dispatcher?;                           false; end
-      def redirect?;                             false; end
-      def engine?;       rack_app.respond_to?(:routes); end
-      def matches?(req);                          true; end
-      def app;                                    self; end
-      def rack_app;                                app; end
+      def dispatcher?;   false; end
+      def redirect?;     false; end
+      def matches?(req);  true; end
+      def app;            self; end
+      def rack_app;        app; end
+
+      def engine?
+        rack_app.is_a?(Class) && rack_app < Rails::Engine
+      end
     end
   end
 end