diff --git a/actionpack/test/dispatch/session/mem_cache_store_test.rb b/actionpack/test/dispatch/session/mem_cache_store_test.rb
index f3cc4f31d8..92544230b2 100644
--- a/actionpack/test/dispatch/session/mem_cache_store_test.rb
+++ b/actionpack/test/dispatch/session/mem_cache_store_test.rb
@@ -1,4 +1,5 @@
 require 'abstract_unit'
+require 'securerandom'
 
 # You need to start a memcached server inorder to run these tests
 class MemCacheStoreTest < ActionDispatch::IntegrationTest