diff --git a/test/unit/lib/redmine/helpers/gantt_test.rb b/test/unit/lib/redmine/helpers/gantt_test.rb
index 37ae51935..d5f0a49b4 100644
--- a/test/unit/lib/redmine/helpers/gantt_test.rb
+++ b/test/unit/lib/redmine/helpers/gantt_test.rb
@@ -21,6 +21,7 @@ class Redmine::Helpers::GanttHelperTest < ActionView::TestCase
   include ApplicationHelper
   include ProjectsHelper
   include IssuesHelper
+  include ERB::Util
 
   def setup
     setup_with_controller