diff --git a/test/unit/ticket_article_communicate_test.rb b/test/unit/ticket_article_communicate_test.rb
index f89002746..533cbe657 100644
--- a/test/unit/ticket_article_communicate_test.rb
+++ b/test/unit/ticket_article_communicate_test.rb
@@ -130,6 +130,7 @@ class TicketArticleCommunicateTest < ActiveSupport::TestCase
 To: customer@example.com
 Subject: some subject
 X-Zammad-Article-Sender: Agent
+X-Loop: yes
 
 Some Text"