diff --git a/activesupport/test/multibyte_utils_test.rb b/activesupport/test/multibyte_utils_test.rb
index 0a2f20d282..1dff944922 100644
--- a/activesupport/test/multibyte_utils_test.rb
+++ b/activesupport/test/multibyte_utils_test.rb
@@ -2,6 +2,7 @@
 
 require 'abstract_unit'
 require 'multibyte_test_helpers'
+require 'active_support/core_ext/kernel/reporting'
 
 class MultibyteUtilsTest < ActiveSupport::TestCase
   include MultibyteTestHelpers