Remove session to allow `with_routing` to be called twice.

Fixes: https://github.com/rails/rails/issues/16814

3 files changed, 41 insertions, 0 deletions

diff --git a/actionpack/lib/action_dispatch/testing/integration.rb b/actionpack/lib/action_dispatch/testing/integration.rb
index c300a4ea0d..fb816aa875 100644
--- a/actionpack/lib/action_dispatch/testing/integration.rb
+++ b/actionpack/lib/action_dispatch/testing/integration.rb
@@ -326,6 +326,10 @@ module ActionDispatch
         @integration_session = Integration::Session.new(app)
       end
 
+      def remove! # :nodoc:
+        @integration_session = nil
+      end
+
       %w(get post patch put head delete cookies assigns
          xml_http_request xhr get_via_redirect post_via_redirect).each do |method|
         define_method(method) do |*args|
diff --git a/actionpack/test/abstract_unit.rb b/actionpack/test/abstract_unit.rb
index 69312e4c22..63c9ab04c9 100644
--- a/actionpack/test/abstract_unit.rb
+++ b/actionpack/test/abstract_unit.rb
@@ -194,6 +194,7 @@ class ActionDispatch::IntegrationTest < ActiveSupport::TestCase
     yield temporary_routes
   ensure
     self.class.app = old_app
+    self.remove!
     silence_warnings { Object.const_set(:SharedTestRoutes, old_routes) }
   end
 
diff --git a/actionpack/test/controller/integration_test.rb b/actionpack/test/controller/integration_test.rb
index d91a1657b3..27b30536b0 100644
--- a/actionpack/test/controller/integration_test.rb
+++ b/actionpack/test/controller/integration_test.rb
@@ -814,3 +814,39 @@ class HeadWithStatusActionIntegrationTest < ActionDispatch::IntegrationTest
     assert_response :ok
   end
 end
+
+class IntegrationWithRoutingTest < ActionDispatch::IntegrationTest
+  class FooController < ActionController::Base
+    def index
+      render plain: 'ok'
+    end
+  end
+
+  def test_with_routing_resets_session
+    klass_namespace = self.class.name.underscore
+
+    with_routing do |routes|
+      routes.draw do
+        namespace klass_namespace do
+          resources :foo, path: '/with'
+        end
+      end
+
+      get '/integration_with_routing_test/with'
+      assert_response 200
+      assert_equal 'ok', response.body
+    end
+
+    with_routing do |routes|
+      routes.draw do
+        namespace klass_namespace do
+          resources :foo, path: '/routing'
+        end
+      end
+
+      get '/integration_with_routing_test/routing'
+      assert_response 200
+      assert_equal 'ok', response.body
+    end
+  end
+end