diff --git a/test/functional/dmsf_controller_test.rb b/test/functional/dmsf_controller_test.rb
index 53140016..00ed5287 100644
--- a/test/functional/dmsf_controller_test.rb
+++ b/test/functional/dmsf_controller_test.rb
@@ -18,6 +18,7 @@
 # <https://www.gnu.org/licenses/>.
 
 require File.expand_path('../../test_helper', __FILE__)
+require File.expand_path('../../../lib/redmine_dmsf/dmsf_zip', __FILE__)
 
 # DMSF controller
 class DmsfControllerTest < RedmineDmsf::Test::TestCase