gistfile1.txt

diff --git a/nova/tests/functional/api/client.py b/nova/tests/functional/api/client.py
index fe88814..451302a 100644
--- a/nova/tests/functional/api/client.py
+++ b/nova/tests/functional/api/client.py
@@ -170,6 +170,9 @@ class TestOpenStackClient(object):
         headers['X-Auth-Token'] = auth_result['x-auth-token']
         if self.microversion:
             headers['X-OpenStack-Nova-API-Version'] = self.microversion
+        elif 'X-OpenStack-Nova-API-Version' in headers:
+            raise Exception('X-OpenStack-Nova-API-Version should be set on '
+                            'microversion attribute in API client.')
 
         response = self.request(full_uri, **kwargs)