Delete concerns_executes_block_in_context_of_current_mapper test

actionpack/test/dispatch/routing/concerns_test.rb

@@ -111,14 +111,4 @@ class RoutingConcernsTest < ActionDispatch::IntegrationTest
 
     assert_equal "No concern named foo was found!", e.message
   end
-
-  def test_concerns_executes_block_in_context_of_current_mapper
-    mapper = ActionDispatch::Routing::Mapper.new(ActionDispatch::Routing::RouteSet.new)
-    mapper.concern :test_concern do
-      resources :things
-      return self
-    end
-
-    assert_equal mapper, mapper.concerns(:test_concern)
-  end
 end