diff --git a/tests/checker/ftpserver.py b/tests/checker/ftpserver.py
index 953d1175..dfff43c6 100644
--- a/tests/checker/ftpserver.py
+++ b/tests/checker/ftpserver.py
@@ -17,7 +17,6 @@
 """
 Define http test support classes for LinkChecker tests.
 """
-import sys
 import os
 import time
 import threading
@@ -52,7 +51,7 @@ class FtpServerTest (LinkCheckTest):
 def start_server (host, port):
     def line_logger(msg):
         if "kill" in msg:
-            sys.exit(0)
+            raise KeyboardInterrupt()
 
     from pyftpdlib import ftpserver
     authorizer = ftpserver.DummyAuthorizer()