this test also

railties/test/railties/shared_tests.rb

@@ -10,17 +10,6 @@ module RailtiesTest
       @app ||= Rails.application
     end
 
-    def test_serving_sprockets_assets
-      @plugin.write "app/assets/javascripts/engine.js.erb", "<%= :alert %>();"
-
-      boot_rails
-      require 'rack/test'
-      extend Rack::Test::Methods
-
-      get "/assets/engine.js"
-      assert_match "alert()", last_response.body
-    end
-
     def test_rake_environment_can_be_called_in_the_engine_or_plugin
       boot_rails