tests: simplify test assertion

test/test_api_rql.py

@@ -155,12 +155,14 @@
         ]
         response = self.make_rql_request(queries, status=400)
 
-        assert response == {
-            "data": None,
-            "message": "781 (in_group-subject): at least one relation in_group is "
-            "required on CWUser (781)",
-            "title": "ValidationError",
-        }
+        self.assertIn(
+            "(in_group-subject): at least one relation in_group is required on CWUser",
+            response["message"],
+        )
+        self.assertEqual(
+            "ValidationError",
+            response["title"],
+        )
 
         # Check user not added, request should be rolled back
         queries = [