diff --git a/tests/run-tests.py b/tests/run-tests.py
--- a/tests/run-tests.py
+++ b/tests/run-tests.py
@@ -255,9 +255,8 @@
     else:
         family = socket.AF_INET
     try:
-        s = socket.socket(family, socket.SOCK_STREAM)
-        s.bind(('localhost', port))
-        s.close()
+        with socket.socket(family, socket.SOCK_STREAM) as s:
+            s.bind(('localhost', port))
         return True
     except socket.error as exc:
         if exc.errno not in (