diff --git a/app/helpers/markup_helper.rb b/app/helpers/markup_helper.rb
index 0009cad86c4..941cfce8370 100644
--- a/app/helpers/markup_helper.rb
+++ b/app/helpers/markup_helper.rb
@@ -1,6 +1,9 @@
 require 'nokogiri'
 
 module MarkupHelper
+  include ActionView::Helpers::TagHelper
+  include ActionView::Context
+
   def plain?(filename)
     Gitlab::MarkupHelper.plain?(filename)
   end
diff --git a/spec/workers/project_cache_worker_spec.rb b/spec/workers/project_cache_worker_spec.rb
index c23ffdf99c0..a4ba5f7c943 100644
--- a/spec/workers/project_cache_worker_spec.rb
+++ b/spec/workers/project_cache_worker_spec.rb
@@ -45,6 +45,18 @@ describe ProjectCacheWorker do
 
         worker.perform(project.id, %w(readme))
       end
+
+      context 'with plain readme' do
+        it 'refreshes the method caches' do
+          allow(MarkupHelper).to receive(:gitlab_markdown?).and_return(false)
+          allow(MarkupHelper).to receive(:plain?).and_return(true)
+
+          expect_any_instance_of(Repository).to receive(:refresh_method_caches).
+                                                  with(%i(readme)).
+                                                  and_call_original
+          worker.perform(project.id, %w(readme))
+        end
+      end
     end
   end