Add spec for Turn on Service Desk.

spec/ee/spec/features/issues/service_desk_spec.rb

 require 'spec_helper'
 
-describe 'Service Desk Issue Tracker' do
+describe 'Service Desk Issue Tracker', js: true do
   let(:project) { create(:project, :private, service_desk_enabled: true) }
   let(:user) { create(:user) }
 
@@ -15,20 +15,23 @@ describe 'Service Desk Issue Tracker' do
   describe 'navigation to service desk' do
     before do
       visit project_path(project)
-      find('.nav-links .shortcuts-issues').trigger('click')
+      find('.sidebar-top-level-items .shortcuts-issues').trigger('click')
       find('a[title="Service Desk"]').trigger('click')
     end
 
-    it 'can navigate to the service desk from link in the sidebar', js: true do
+    it 'can navigate to the service desk from link in the sidebar' do
       expect(page).to have_content('Use Service Desk to connect with your users')
     end
   end
 
-  describe 'issues list', js: true do
+  describe 'issues list' do
     context 'when service desk has not been activated' do
+      let(:project_without_service_desk) { create(:project, :private, service_desk_enabled: false) }
+
       describe 'service desk info content' do
         before do
-          visit service_desk_project_issues_path(project)
+          project_without_service_desk.add_master(user)
+          visit service_desk_project_issues_path(project_without_service_desk)
         end
 
         it 'displays the large info box' do
@@ -38,6 +41,10 @@ describe 'Service Desk Issue Tracker' do
         it 'has a link to the documentation' do
           expect(page).to have_link('Read more', href: help_page_path('user/project/service_desk'))
         end
+
+        it 'does show a button configure service desk' do
+          expect(page).to have_link('Turn on Service Desk')
+        end
       end
     end