diff --git a/tests/system_tests_tcp_adaptor.py b/tests/system_tests_tcp_adaptor.py
index b36fa791f..63c4eb2cd 100644
--- a/tests/system_tests_tcp_adaptor.py
+++ b/tests/system_tests_tcp_adaptor.py
@@ -168,17 +168,17 @@ def __init__(self, test_name, client_n, logger, client, server, size,
                                           delay_close=delay_close)
 
         except Exception as exc:
-            self.e_client.error = "TCP_TEST TcpAdaptor_runner_%s failed. Exception: %s" % \
-                                  (self.name, traceback.format_exc())
-            self.logger.log(self.e_client.error)
-            raise Exception(self.e_client.error)
+            error = f"TCP_TEST TcpAdaptor_runner_{self.name} failed. Exception: {exc}"
+            self.logger.log(error)
+            raise
 
     def wait(self):
         """
         Block until the client completes. An exception is raised if the client
         failed.
         """
-        self.e_client.wait()
+        if self.e_client is not None:
+            self.e_client.wait()
 
 
 class TcpAdaptorBase(TestCase):