add test for CreateHeader Extract method
diff --git a/openstack/objectstorage/v1/containers/fixtures.go b/openstack/objectstorage/v1/containers/fixtures.go
index 1c0a915..9c84bce 100644
--- a/openstack/objectstorage/v1/containers/fixtures.go
+++ b/openstack/objectstorage/v1/containers/fixtures.go
@@ -94,6 +94,7 @@
 		th.TestHeader(t, r, "Accept", "application/json")
 
 		w.Header().Add("X-Container-Meta-Foo", "bar")
+		w.Header().Add("X-Trans-Id", "1234567")
 		w.WriteHeader(http.StatusNoContent)
 	})
 }