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

CHANGELOG

@@ -12,6 +12,7 @@ v 8.12.0 (unreleased)
   - Reduce contributions calendar data payload (ClemMakesApps)
   - Add `web_url` field to issue, merge request, and snippet API objects (Ben Boeckel)
   - Set path for all JavaScript cookies to honor GitLab's subdirectory setting !5627 (Mike Greiling)
+  - Fix bug where pagination is still displayed despite all todos marked as done (ClemMakesApps)
   - Shorten task status phrase (ClemMakesApps)
   - Add hover color to emoji icon (ClemMakesApps)
   - Fix branches page dropdown sort alignment (ClemMakesApps)

app/assets/javascripts/todos.js

@@ -66,7 +66,7 @@
         success: (function(_this) {
           return function(data) {
             $this.remove();
-            $('.js-todos-list').remove();
+            $('.prepend-top-default').html('<div class="nothing-here-block">You\'re all done!</div>');
             return _this.updateBadges(data);
           };
         })(this)

app/views/dashboard/todos/index.html.haml

@@ -66,7 +66,7 @@
   - if @todos.any?
     .js-todos-options{ data: {per_page: @todos.limit_value, current_page: @todos.current_page, total_pages: @todos.total_pages} }
     - @todos.group_by(&:project).each do |group|
-      .panel.panel-default.panel-small.js-todos-list
+      .panel.panel-default.panel-small
         - project = group[0]
         .panel-heading
           = link_to project.name_with_namespace, namespace_project_path(project.namespace, project)

features/steps/dashboard/todos.rb

@@ -54,6 +54,7 @@ class Spinach::Features::DashboardTodos < Spinach::FeatureSteps
     page.within('.todos-pending-count') { expect(page).to have_content '0' }
     expect(page).to have_content 'To do 0'
     expect(page).to have_content 'Done 4'
+    expect(page).to have_content "You're all done!"
     expect(page).not_to have_link project.name_with_namespace
     should_not_see_todo "John Doe assigned you merge request #{merge_request.to_reference}"
     should_not_see_todo "John Doe mentioned you on issue #{issue.to_reference}"

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