diff --git a/stubs/cmdtests/smtpd.script b/stubs/cmdtests/smtpd.script
index 79541da..659732a 100755
--- a/stubs/cmdtests/smtpd.script
+++ b/stubs/cmdtests/smtpd.script
@@ -51,7 +51,7 @@ def main():
       env['STUB_SMTPD_DATADIR'] = smtpddir
 
       smtpd = subprocess.Popen([os.path.join(stubdir, 'smtpd'), '--port=4321'],
-                               env=env)
+                               stdin=subprocess.DEVNULL, env=env)
 
       time.sleep(1)
 
diff --git a/stubs/smtpd b/stubs/smtpd
index 1c8e8ad..9c0c337 100755
--- a/stubs/smtpd
+++ b/stubs/smtpd
@@ -36,6 +36,7 @@ import aiosmtpd.controller
 import os
 import os.path
 import sys
+import signal
 
 datadir = None
 
@@ -81,8 +82,9 @@ def run(args):
     # Run the event loop in a separate thread.
     controller.start()
 
-    # Wait for the user to press Return.
-    input()
+    # wait until a signal is received
+    signal.pause()
+
     controller.stop()