Merge branch '469149-new-merge-trains-link' into 'master'

Add new merge trains link

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/160757



Merged-by: Terri Chu <tchu@gitlab.com>
Approved-by: Veethika Mishra <6115425-veethika@users.noreply.gitlab.com>
Approved-by: Serhii Yarynovskyi <syarynovskyi@gitlab.com>
Approved-by: Ammar Alakkad <aalakkad@gitlab.com>
Approved-by: Artur Fedorov <afedorov@gitlab.com>
Approved-by: Terri Chu <tchu@gitlab.com>
Reviewed-by: Terri Chu <tchu@gitlab.com>
Reviewed-by: Veethika Mishra <6115425-veethika@users.noreply.gitlab.com>
Reviewed-by: Artur Fedorov <afedorov@gitlab.com>
Co-authored-by: Payton Burdette <pburdette@gitlab.com>

app/views/projects/merge_requests/_nav_btns.html.haml

+= render_if_exists 'projects/merge_requests/merge_trains_button'
 - if @can_bulk_update
   = render Pajamas::ButtonComponent.new(type: :submit, button_options: { class: 'gl-mr-3 js-bulk-update-toggle' }) do
     = _("Bulk edit")

ee/app/views/projects/merge_requests/_merge_trains_button.html.haml

+- if merge_trains_available? && can?(@current_user, :read_merge_train, @project)
+  = render Pajamas::ButtonComponent.new(href: project_merge_trains_path(@project)) do
+    = _("Merge trains")

ee/spec/features/merge_requests/user_sees_nav_buttons_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Merge request > User sees nav buttons', :js, feature_category: :code_review_workflow do
+  let_it_be(:project) { create(:project) }
+  let_it_be(:maintainer) { create(:user) }
+  let_it_be(:guest) { create(:user) }
+  let_it_be(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
+
+  before_all do
+    project.add_maintainer(maintainer)
+    project.add_guest(guest)
+  end
+
+  context 'as a maintainer' do
+    before do
+      project.update!(merge_trains_enabled: true)
+      stub_licensed_features(merge_trains: true)
+
+      sign_in(maintainer)
+
+      visit project_merge_requests_path(project)
+    end
+
+    it 'shows the "New merge request" link' do
+      expect(page).to have_link 'New merge request', href: project_new_merge_request_path(project)
+    end
+
+    it 'shows the "Bulk edit" button' do
+      expect(page).to have_button 'Bulk edit'
+    end
+
+    it 'shows the "Merge trains" link' do
+      expect(page).to have_link 'Merge trains', href: project_merge_trains_path(project)
+    end
+  end
+
+  context 'as a guest' do
+    before do
+      project.update!(merge_trains_enabled: true)
+      stub_licensed_features(merge_trains: true)
+
+      sign_in(guest)
+
+      visit project_merge_requests_path(project)
+    end
+
+    it 'does not show the "New merge request" link' do
+      expect(page).not_to have_link 'New merge request'
+    end
+
+    it 'does not show the "Bulk edit" button' do
+      expect(page).not_to have_button 'Bulk edit'
+    end
+
+    it 'does not show the "Merge trains" link' do
+      expect(page).not_to have_link 'Merge trains'
+    end
+  end
+end

spec/features/merge_requests/user_sees_nav_buttons_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe 'Merge request > User sees nav buttons', feature_category: :code_review_workflow do
+  let_it_be(:project) { create(:project) }
+  let_it_be(:maintainer) { create(:user) }
+  let_it_be(:guest) { create(:user) }
+  let_it_be(:merge_request) { create(:merge_request, source_project: project, target_project: project) }
+
+  before_all do
+    project.add_maintainer(maintainer)
+    project.add_guest(guest)
+  end
+
+  context 'as a maintainer' do
+    before do
+      sign_in(maintainer)
+
+      visit project_merge_requests_path(project)
+    end
+
+    it 'shows the "New merge request" button' do
+      expect(page).to have_link 'New merge request', href: project_new_merge_request_path(project)
+    end
+
+    it 'shows the "Bulk edit" button' do
+      expect(page).to have_button 'Bulk edit'
+    end
+
+    it 'does not show the "Merge trains" button' do
+      expect(page).not_to have_link 'Merge trains'
+    end
+  end
+
+  context 'as a guest' do
+    before do
+      sign_in(guest)
+
+      visit project_merge_requests_path(project)
+    end
+
+    it 'does not show the "New merge request" button' do
+      expect(page).not_to have_link 'New merge request'
+    end
+
+    it 'does not show the "Bulk edit" button' do
+      expect(page).not_to have_button 'Bulk edit'
+    end
+
+    it 'does not show the "Merge trains" button' do
+      expect(page).not_to have_link 'Merge trains'
+    end
+  end
+end