diff --git a/neutron/tests/common/net_helpers.py b/neutron/tests/common/net_helpers.py
index a79c1ff20b0..520fb359ae0 100644
--- a/neutron/tests/common/net_helpers.py
+++ b/neutron/tests/common/net_helpers.py
@@ -314,7 +314,7 @@ class NetcatTester(object):
 
     def establish_connection(self):
         if self._client_process:
-            raise RuntimeError('%(proto)s connection to $(ip_addr)s is already'
+            raise RuntimeError('%(proto)s connection to %(ip_addr)s is already'
                                ' established' %
                                {'proto': self.protocol,
                                 'ip_addr': self.address})