diff --git a/run_tests.py b/run_tests.py
index <HASH>..<HASH> 100755
--- a/run_tests.py
+++ b/run_tests.py
@@ -58,7 +58,7 @@ def wait_until_stop():
 
 
 def start_server():
-    sys.stderr = open("/dev/null", "w")
+    sys.stderr = open(os.devnull, "w")
     env.process = Process(target=start_flask_app, args=(env.host, env.port))
     env.process.daemon = True
     env.process.start()
Replace "/dev/null" with os.devnull (#<I>)