diff --git a/test/test_thread_pool.rb b/test/test_thread_pool.rb
index 3799b8ef..c3df275c 100644
--- a/test/test_thread_pool.rb
+++ b/test/test_thread_pool.rb
@@ -167,6 +167,8 @@ class TestThreadPool < Test::Unit::TestCase
       Thread.pass until finished
     }
 
+    pool.clean_thread_locals = true
+
     n.times { pool << 1 }
 
     finished = true