Fixes #3279 - "Next ticket in overview" is clickable for the last ticket in the overview

app/assets/javascripts/app/views/ticket_zoom/overview_navigator.jst.eco

@@ -3,7 +3,7 @@
 </div>
 <ul class="pagination">
   <li <% if !@previous: %>class="disabled"<% end %> title="<%- @Ti( 'Previous in overview' ) %>">
-    <a class="centered previous" href="<% if @previous: %><%- @previous.uiUrl() %><% end %>" data-id="<% if @previous: %><%- @previous.id %><% end %>">
+    <a class="centered previous" href="<% if @previous: %><%- @previous.uiUrl() %><% end %>" <% if @previous: %>data-id="<%- @previous.id %>"<% end %>>
       <% if @previous: %>
         <%- @Icon('arrow-left') %>
       <% else: %>
@@ -11,7 +11,7 @@
       <% end %>
     </a>
   <li <% if !@next: %>class="disabled"<% end %> title="<%- @Ti( 'Next in overview' ) %>">
-    <a class="centered next" href="<% if @next: %><%- @next.uiUrl() %><% end %>" data-id="<% if @next: %><%- @next.id %><% end %>">
+    <a class="centered next" href="<% if @next: %><%- @next.uiUrl() %><% end %>" <% if @next: %>data-id="<%- @next.id %>"<% end %>>
       <% if @next: %>
         <%- @Icon('arrow-right') %>
       <% else: %>

spec/system/ticket/zoom_spec.rb

@@ -1112,6 +1112,59 @@ RSpec.describe 'Ticket zoom', type: :system do
 
       expect { find(:element_containing, macro.name).click }.to change { current_url }
     end
+  end
 
+  # https://github.com/zammad/zammad/issues/3279
+  describe 'previous/next clickability when at last or first ticket' do
+    let(:ticket_a)          { create(:ticket, title: 'ticket a', group: Group.first) }
+    let(:ticket_b)          { create(:ticket, title: 'ticket b', group: Group.first) }
+
+    before do
+      ticket_a && ticket_b
+
+      visit 'ticket/view/all_unassigned'
+    end
+
+    it 'previous is not clickable for the first item' do
+      open_nth_item(0)
+
+      expect { click '.pagination .previous' }.not_to change { current_url }
+    end
+
+    it 'next is clickable for the first item' do
+      open_nth_item(0)
+
+      expect { click '.pagination .next' }.to change { current_url }
+    end
+
+    it 'previous is clickable for the middle item' do
+      open_nth_item(1)
+
+      expect { click '.pagination .previous' }.to change { current_url }
+    end
+
+    it 'next is clickable for the middle item' do
+      open_nth_item(1)
+
+      expect { click '.pagination .next' }.to change { current_url }
+    end
+
+    it 'previous is clickable for the last item' do
+      open_nth_item(2)
+
+      expect { click '.pagination .previous' }.to change { current_url }
+    end
+
+    it 'next is not clickable for the last item' do
+      open_nth_item(2)
+
+      expect { click '.pagination .next' }.not_to change { current_url }
+    end
+
+    def open_nth_item(nth)
+      within :active_content do
+        find_all('.table tr.item .user-popover')[nth].click
+      end
+    end
   end
 end