Merge branch 'fix-todo-pagination' into 'master'

Fix bug where pagination is still displayed despite all todos marked as done

## What does this MR do?
Changes the todo `mark all as done` button callback to remove pagination and add user friendly text `"You're all done!"` so that it is consistent with what the page should look like after refreshing

## Are there points in the code the reviewer needs to double check?
Shouldn't be

## Why was this MR needed?
Resolve existing UI inconsistency

## Screenshots (if relevant)
Before:
![8xDRiXB1TL](/uploads/479edbdedf8d468b4c5e502f36a0c19f/8xDRiXB1TL.gif)

After:
![q4XDxhujPX](/uploads/3566eb538e6ad5a2d32b78351b9bc47d/q4XDxhujPX.gif)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?
Closes #21048

See merge request !6113

1 files changed, 14 insertions, 0 deletions

diff --git a/spec/features/todos/todos_spec.rb b/spec/features/todos/todos_spec.rb
index 32544f3f538..fc555a74f30 100644
--- a/spec/features/todos/todos_spec.rb
+++ b/spec/features/todos/todos_spec.rb
@@ -118,6 +118,20 @@ describe 'Dashboard Todos', feature: true do
           expect(page).to have_css("#todo_#{Todo.first.id}")
         end
       end
+
+      describe 'mark all as done', js: true do
+        before do
+          visit dashboard_todos_path
+          click_link('Mark all as done')
+        end
+
+        it 'shows "All done" message!' do
+          within('.todos-pending-count') { expect(page).to have_content '0' }
+          expect(page).to have_content 'To do 0'
+          expect(page).to have_content "You're all done!"
+          expect(page).not_to have_selector('.gl-pagination')
+        end
+      end
     end
 
     context 'User has a Todo in a project pending deletion' do