Add a controller test for the new 'diff_view' cookie

app/controllers/projects/application_controller.rb

@@ -26,15 +26,13 @@ class Projects::ApplicationController < ApplicationController
     end
   end
 
-  protected
+  private
 
   def apply_diff_view_cookie!
     view = params[:view] || cookies[:diff_view]
     cookies.permanent[:diff_view] = params[:view] = view if view
   end
 
-  private
-
   def builds_enabled
     return render_404 unless @project.builds_enabled?
   end

spec/controllers/projects/merge_requests_controller_spec.rb

@@ -199,6 +199,18 @@ describe Projects::MergeRequestsController do
     end
   end
 
+  describe 'GET diffs with view' do
+    it 'saves the preferred diff view in a cookie' do
+      get :diffs,
+          namespace_id: project.namespace.to_param,
+          project_id: project.to_param,
+          id: merge_request.iid,
+          view: 'parallel'
+
+      expect(response.cookies['diff_view']).to eq('parallel')
+    end
+  end
+
   describe 'GET commits' do
     def go(format: 'html')
       get :commits,