diff --git a/activesupport/test/testing/file_fixtures_test.rb b/activesupport/test/testing/file_fixtures_test.rb
index <HASH>..<HASH> 100644
--- a/activesupport/test/testing/file_fixtures_test.rb
+++ b/activesupport/test/testing/file_fixtures_test.rb
@@ -1,5 +1,7 @@
 require 'abstract_unit'
 
+require 'pathname'
+
 class FileFixturesTest < ActiveSupport::TestCase
   self.file_fixture_path = File.expand_path("../../file_fixtures", __FILE__)
Pathname might not be always initialized.

Require 'pathname' explicitly