Add spec for note edit and fix one commented spec.

changelogs/unreleased/single-edit-comment-widget-2.yml

+---
+title: Refactored note edit form to improve frontend performance on MR and Issues
+  pages, especially pages with has a lot of discussions in it
+merge_request: 8356
+author:

spec/features/notes_on_merge_requests_spec.rb

@@ -78,7 +78,7 @@ describe 'Comments', feature: true do
       describe 'editing the note' do
         before do
           find('.note').hover
-          find(".js-note-edit").click
+          find('.js-note-edit').click
         end
 
         it 'shows the note edit form and hide the note body' do
@@ -89,14 +89,29 @@ describe 'Comments', feature: true do
           end
         end
 
-        # TODO: fix after 7.7 release
-        # it "should reset the edit note form textarea with the original content of the note if cancelled" do
-        #   within(".current-note-edit-form") do
-        #     fill_in "note[note]", with: "Some new content"
-        #     find(".btn-cancel").click
-        #     expect(find(".js-note-text", visible: false).text).to eq note.note
-        #   end
-        # end
+        it 'should reset the edit note form textarea with the original content of the note if cancelled' do
+          within('.current-note-edit-form') do
+            fill_in 'note[note]', with: 'Some new content'
+            find('.btn-cancel').click
+            expect(find('.js-note-text', visible: false).text).to eq ''
+          end
+        end
+
+        it 'allows using markdown buttons after saving a note and then trying to edit it again' do
+          page.within('.current-note-edit-form') do
+            fill_in 'note[note]', with: 'This is the new content'
+            find('.btn-save').click
+          end
+
+          find('.note').hover
+          find('.js-note-edit').click
+
+          page.within('.current-note-edit-form') do
+            expect(find('#note_note').value).to eq('This is the new content')
+            find('.js-md:first-child').click
+            expect(find('#note_note').value).to eq('This is the new content****')
+          end
+        end
 
         it 'appends the edited at time to the note' do
           page.within('.current-note-edit-form') do