Present state indication on GFM preview

app/controllers/concerns/preview_markdown.rb

@@ -10,6 +10,7 @@ module PreviewMarkdown
       when 'wikis'    then { pipeline: :wiki, project_wiki: @project_wiki, page_slug: params[:id] }
       when 'snippets' then { skip_project_check: true }
       when 'groups'   then { group: group }
+      when 'projects' then { issuable_state_filter_enabled: true }
       else {}
       end
 

changelogs/unreleased/31583-osw-gfm-complete-status-indication.yml

+---
+title: Present state indication on GFM preview
+merge_request:
+author:
+type: added

spec/controllers/projects_controller_spec.rb

@@ -616,13 +616,40 @@ describe ProjectsController do
   end
 
   describe 'POST #preview_markdown' do
-    it 'renders json in a correct format' do
+    before do
       sign_in(user)
+    end
 
+    it 'renders json in a correct format' do
       post :preview_markdown, namespace_id: public_project.namespace, id: public_project, text: '*Markdown* text'
 
       expect(JSON.parse(response.body).keys).to match_array(%w(body references))
     end
+
+    context 'state filter on references' do
+      let(:issue) { create(:issue, :closed, project: public_project) }
+      let(:merge_request) { create(:merge_request, :closed, target_project: public_project) }
+
+      it 'renders JSON body with state filter for issues' do
+        post :preview_markdown, namespace_id: public_project.namespace,
+                                id: public_project,
+                                text: issue.to_reference
+
+        json_response = JSON.parse(response.body)
+
+        expect(json_response['body']).to match(/\##{issue.iid} \(closed\)/)
+      end
+
+      it 'renders JSON body with state filter for MRs' do
+        post :preview_markdown, namespace_id: public_project.namespace,
+                                id: public_project,
+                                text: merge_request.to_reference
+
+        json_response = JSON.parse(response.body)
+
+        expect(json_response['body']).to match(/\!#{merge_request.iid} \(closed\)/)
+      end
+    end
   end
 
   describe '#ensure_canonical_path' do