There is no need to open AC::Base three times to setup tests.

actionpack/test/abstract_unit.rb

@@ -274,11 +274,27 @@ class Rack::TestCase < ActionController::IntegrationTest
   end
 end
 
-class ActionController::Base
+module ActionController
-  def self.test_routes(&block)
+  class Base
-    routes = ActionDispatch::Routing::RouteSet.new
+    include ActionController::Testing
-    routes.draw(&block)
+    # This stub emulates the Railtie including the URL helpers from a Rails application
-    include routes.url_helpers
+    include SharedTestRoutes.url_helpers
+
+    self.view_paths = FIXTURE_LOAD_PATH
+
+    def self.test_routes(&block)
+      routes = ActionDispatch::Routing::RouteSet.new
+      routes.draw(&block)
+      include routes.url_helpers
+    end
+  end
+
+  class TestCase
+    include ActionDispatch::TestProcess
+
+    setup do
+      @routes = SharedTestRoutes
+    end
   end
 end
 
@@ -294,26 +310,3 @@ module ActionView
     end
   end
 end
-
-module ActionController
-  class Base
-    include ActionController::Testing
-  end
-
-  Base.view_paths = FIXTURE_LOAD_PATH
-
-  class TestCase
-    include ActionDispatch::TestProcess
-
-    setup do
-      @routes = SharedTestRoutes
-    end
-  end
-end
-
-# This stub emulates the Railtie including the URL helpers from a Rails application
-module ActionController
-  class Base
-    include SharedTestRoutes.url_helpers
-  end
-end