diff --git a/test/global_test_helper.rb b/test/global_test_helper.rb
index 6606ee52..afdbda6a 100644
--- a/test/global_test_helper.rb
+++ b/test/global_test_helper.rb
@@ -194,5 +194,10 @@ def assert_dashboard_query_blocks(blocks = [])
     def columns_in_projects_list
       css_select('table.projects thead th').map(&:text)
     end
+
+    # should be dropped after dropping Rails 6.x support / Redmine 5.1 support
+    def self.fixture_date_format(date)
+      date.try(:to_fs, :db) || date.to_s(:db)
+    end
   end
 end