Add explicit message when no runners on admin

app/views/admin/runners/index.html.haml

@@ -58,6 +58,7 @@
 
   %br
 
+  - if @runners.any?
     .table-holder
       %table.table
         %thead
@@ -75,3 +76,5 @@
         - @runners.each do |runner|
           = render "admin/runners/runner", runner: runner
     = paginate @runners, theme: "gitlab"
+  - else
+    .nothing-here-block No runners found

changelogs/unreleased/33846-no-runner-for-admin.yml

+---
+title: Add explicit message when no runners on admin
+merge_request: 12266
+author: Takuya Noguchi

spec/features/admin/admin_runners_spec.rb

@@ -9,9 +9,11 @@ describe "Admin Runners" do
   end
 
   describe "Runners page" do
+    let(:pipeline) { create(:ci_pipeline) }
+
+    context "when there are runners" do
       before do
         runner = FactoryGirl.create(:ci_runner, contacted_at: Time.now)
-      pipeline = FactoryGirl.create(:ci_pipeline)
         FactoryGirl.create(:ci_build, pipeline: pipeline, runner_id: runner.id)
         visit admin_runners_path
       end
@@ -25,16 +27,37 @@ describe "Admin Runners" do
         before do
           FactoryGirl.create :ci_runner, description: 'runner-foo'
           FactoryGirl.create :ci_runner, description: 'runner-bar'
+        end
 
+        it 'shows correct runner when description matches' do
           search_form = find('#runners-search')
           search_form.fill_in 'search', with: 'runner-foo'
           search_form.click_button 'Search'
-      end
 
-      it 'shows correct runner' do
           expect(page).to have_content("runner-foo")
           expect(page).not_to have_content("runner-bar")
         end
+
+        it 'shows no runner when description does not match' do
+          search_form = find('#runners-search')
+          search_form.fill_in 'search', with: 'runner-baz'
+          search_form.click_button 'Search'
+
+          expect(page).to have_text 'No runners found'
+        end
+      end
+    end
+
+    context "when there are no runners" do
+      before do
+        visit admin_runners_path
+      end
+
+      it 'has all necessary texts including no runner message' do
+        expect(page).to have_text "To register a new Runner"
+        expect(page).to have_text "Runners with last contact more than a minute ago: 0"
+        expect(page).to have_text 'No runners found'
+      end
     end
   end