Merge branch '17932-move-to-project-dropdown' into 'master'

Move to project dropdown with infinite scroll for better performance

## What does this MR do?

On the Move dropdown on the edit issue page we introduced infinite scrolling to just return a limited number of projects, 50 items. So if the user can move the issue to 50 or more items when scroll down on the list a new set of projects will be requested to the server.

## Are there points in the code the reviewer needs to double check?

## Why was this MR needed?

See #17932

## What are the relevant issue numbers?

Closes #17932

## Screenshots (if relevant)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- ~~[ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)~~
- ~~[ ] API support 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)

See merge request !5686

1 files changed, 50 insertions, 0 deletions

diff --git a/spec/controllers/autocomplete_controller_spec.rb b/spec/controllers/autocomplete_controller_spec.rb
index 44128a43362..a121cb2fc97 100644
--- a/spec/controllers/autocomplete_controller_spec.rb
+++ b/spec/controllers/autocomplete_controller_spec.rb
@@ -237,6 +237,56 @@ describe AutocompleteController do
       end
     end
 
+    context 'authorized projects apply limit' do
+      before do
+        authorized_project2 = create(:project)
+        authorized_project3 = create(:project)
+
+        authorized_project.team << [user, :master]
+        authorized_project2.team << [user, :master]
+        authorized_project3.team << [user, :master]
+
+        stub_const 'MoveToProjectFinder::PAGE_SIZE', 2
+      end
+
+      describe 'GET #projects with project ID' do
+        before do
+          get(:projects, project_id: project.id)
+        end
+
+        let(:body) { JSON.parse(response.body) }
+
+        it do
+          expect(body).to be_kind_of(Array)
+          expect(body.size).to eq 3 # Of a total of 4
+        end
+      end
+    end
+
+    context 'authorized projects with offset' do
+      before do
+        authorized_project2 = create(:project)
+        authorized_project3 = create(:project)
+
+        authorized_project.team << [user, :master]
+        authorized_project2.team << [user, :master]
+        authorized_project3.team << [user, :master]
+      end
+
+      describe 'GET #projects with project ID and offset_id' do
+        before do
+          get(:projects, project_id: project.id, offset_id: authorized_project.id)
+        end
+
+        let(:body) { JSON.parse(response.body) }
+
+        it do
+          expect(body.detect { |item| item['id'] == 0 }).to be_nil # 'No project' is not there
+          expect(body.detect { |item| item['id'] == authorized_project.id }).to be_nil # Offset project is not there either
+        end
+      end
+    end
+
     context 'authorized projects without admin_issue ability' do
       before(:each) do
         authorized_project.team << [user, :guest]