diff --git a/test/unit/helpers/application_helper_test.rb b/test/unit/helpers/application_helper_test.rb
index 5f5eefa19..52d49743d 100644
--- a/test/unit/helpers/application_helper_test.rb
+++ b/test/unit/helpers/application_helper_test.rb
@@ -610,6 +610,7 @@ EXPECTED
                 Date.today - 100 => 'about 3 months late',
                 Date.today - 20000 => 'over 54 years late',
                }
+    ::I18n.locale = :en
     to_test.each do |date, expected|
       assert_equal expected, due_date_distance_in_words(date)
     end