diff --git a/actionpack/lib/action_dispatch/request/session.rb b/actionpack/lib/action_dispatch/request/session.rb
index 42890225fa895d111a886304373f384f04df08a4..47568f6ad0050b262557d7623d5e575a90264e89 100644
--- a/actionpack/lib/action_dispatch/request/session.rb
+++ b/actionpack/lib/action_dispatch/request/session.rb
@@ -9,7 +9,7 @@ class Session # :nodoc:
 
       # Singleton object used to determine if an optional param wasn't specified
       Unspecified = Object.new
-      
+
       # Creates a session hash, merging the properties of the previous session if any
       def self.create(store, req, default_options)
         session_was = find req
@@ -198,6 +198,10 @@ def merge!(other)
         @delegate.merge!(other)
       end
 
+      def each(&block)
+        to_hash.each(&block)
+      end
+
       private
 
       def load_for_read!
diff --git a/actionpack/test/dispatch/request/session_test.rb b/actionpack/test/dispatch/request/session_test.rb
index 7dcbcc5c2190fead45db6cd3f8a53f3bf96dabdd..e022e7e21e1b2886c67624a8ee33befff93cdb84 100644
--- a/actionpack/test/dispatch/request/session_test.rb
+++ b/actionpack/test/dispatch/request/session_test.rb
@@ -114,5 +114,31 @@ def delete_session(env, id, options); 123; end
         }.new
       end
     end
+
+    class SessionIntegrationTest < ActionDispatch::IntegrationTest
+      class MySessionApp
+        def call(env)
+          request = Rack::Request.new(env)
+          request.session['hello'] = 'Hello from MySessionApp!'
+          [ 200, {}, ['Hello from MySessionApp!'] ]
+        end
+      end
+
+      Router = ActionDispatch::Routing::RouteSet.new
+      Router.draw do
+        get '/mysessionapp' => MySessionApp.new
+      end
+
+      def app
+        @app ||= RoutedRackApp.new(Router)
+      end
+
+      def test_session_follows_rack_api_contract_1
+        get '/mysessionapp'
+        assert_response :ok
+        assert_equal 'Hello from MySessionApp!', @response.body
+        assert_equal 'Hello from MySessionApp!', session['hello']
+      end
+    end
   end
 end