diff --git a/test/test_model_modules/test_keras_extensions.py b/test/test_model_modules/test_keras_extensions.py
index 17ab4f6d65c95a5a54c9d931818f889acadef532..35188933c476157a6ba8c244d3647f7d6f8bdc59 100644
--- a/test/test_model_modules/test_keras_extensions.py
+++ b/test/test_model_modules/test_keras_extensions.py
@@ -179,6 +179,13 @@ class TestCallbackHandler:
                                                             {"name": "other_clbk", "other_clbk": "callback_other",
                                                              "path": "otherpath"}]
 
+    def test_add_callback_raise(self, clbk_handler):
+        clbk_handler.editable = False
+        with pytest.raises(PermissionError) as einfo:
+            clbk_handler.add_callback("callback_new_instance", "this_path")
+        assert 'CallbackHandler is protected and cannot be edited.' in str(einfo.value)
+
+
     def test_get_callbacks_as_dict(self, clbk_handler_with_dummies):
         clbk = clbk_handler_with_dummies
         assert clbk.get_callbacks() == [{"callback": "callback_new_instance", "path": "this_path"},