Add missing N+1 test to issues spec

spec/requests/api/issues_spec.rb

@@ -509,6 +509,18 @@ describe API::Issues, :mailer do
   describe "GET /projects/:id/issues" do
     let(:base_url) { "/projects/#{project.id}" }
 
+    it 'avoids N+1 queries' do
+      control_count = ActiveRecord::QueryRecorder.new do
+        get api("/projects/#{project.id}/issues", user)
+      end.count
+
+      create(:issue, author: user, project: project)
+
+      expect do
+        get api("/projects/#{project.id}/issues", user)
+      end.not_to exceed_query_limit(control_count)
+    end
+
     it 'returns 404 when project does not exist' do
       get api('/projects/1000/issues', non_member)