diff --git a/shade/tests/unit/base.py b/shade/tests/unit/base.py
index 4bae60e78..b7d8e8588 100644
--- a/shade/tests/unit/base.py
+++ b/shade/tests/unit/base.py
@@ -175,7 +175,7 @@ class RequestsMockTestCase(BaseTestCase):
         self.use_keystone_v3()
         self.__register_uris_called = False
 
-    def get_mock_url(self, service_type, interface, resource=None,
+    def get_mock_url(self, service_type, interface='public', resource=None,
                      append=None, base_url_append=None,
                      qs_elements=None):
         endpoint_url = self.cloud.endpoint_for(