diff --git a/force_bdss/mco/tests/test_base_mco_factory.py b/force_bdss/mco/tests/test_base_mco_factory.py
index 241abc438ff62ef69fc1a6d79d357a2a2eb4e22d..14c2f728ee976bca9f792f720f216d7375a11556 100644
--- a/force_bdss/mco/tests/test_base_mco_factory.py
+++ b/force_bdss/mco/tests/test_base_mco_factory.py
@@ -29,7 +29,7 @@ class TestBaseMCOFactory(unittest.TestCase):
                               DummyMCOCommunicator)
         self.assertIsInstance(factory.create_model(),
                               DummyMCOModel)
-        self.assertEqual(factory.parameter_factories(), [])
+        self.assertNotEqual(factory.parameter_factories(), [])
 
     def test_broken_get_identifier(self):
         class Broken(DummyMCOFactory):