diff --git a/openbsc/tests/smpp_test_runner.py b/openbsc/tests/smpp_test_runner.py
index b6da86ca2..4527ac42b 100644
--- a/openbsc/tests/smpp_test_runner.py
+++ b/openbsc/tests/smpp_test_runner.py
@@ -54,6 +54,8 @@ class TestVTYBase(unittest.TestCase):
         self.vty = obscvty.VTYInteract(appstring, "127.0.0.1", appport)
 
     def tearDown(self):
+        if self.vty:
+            self.vty._close_socket()
         self.vty = None
         osmoutil.end_proc(self.proc)