require "abstract_unit" module ApiWithHelper def my_helper "helper" end end class WithHelpersController < ActionController::API include ActionController::Helpers helper ApiWithHelper def with_helpers render plain: self.class.helpers.my_helper end end class SubclassWithHelpersController < WithHelpersController def with_helpers render plain: self.class.helpers.my_helper end end class WithHelpersTest < ActionController::TestCase tests WithHelpersController def test_with_helpers get :with_helpers assert_equal "helper", response.body end end class SubclassWithHelpersTest < ActionController::TestCase tests WithHelpersController def test_with_helpers get :with_helpers assert_equal "helper", response.body end end