diff --git a/test/functional/test_runner.py b/test/functional/test_runner.py
--- a/test/functional/test_runner.py
+++ b/test/functional/test_runner.py
@@ -473,13 +473,13 @@
 
     # Start our result collection thread.
     t = threading.Thread(target=handle_update_messages)
-    t.setDaemon(True)
+    t.daemon = True
     t.start()
 
     # Start some worker threads
     for j in range(num_jobs):
         t = threading.Thread(target=handle_test_cases)
-        t.setDaemon(True)
+        t.daemon = True
         t.start()
 
     # Push all our test cases into the job queue.