--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/hooks/test/unittest_syncsources.py	Wed Apr 12 16:07:25 2017 +0200
@@ -0,0 +1,35 @@
+# copyright 2017 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
+# contact http://www.logilab.fr/ -- mailto:contact@logilab.fr
+#
+# This file is part of CubicWeb.
+#
+# CubicWeb is free software: you can redistribute it and/or modify it under the
+# terms of the GNU Lesser General Public License as published by the Free
+# Software Foundation, either version 2.1 of the License, or (at your option)
+# any later version.
+#
+# CubicWeb is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Lesser General Public License along
+# with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
+
+from cubicweb import ValidationError
+from cubicweb.devtools.testlib import CubicWebTC
+
+
+class SyncSourcesTC(CubicWebTC):
+
+    def test_cant_add_config_system_source(self):
+        with self.admin_access.cnx() as cnx:
+            source = cnx.find('CWSource').one()
+
+            with self.assertRaises(ValidationError):
+                source.cw_set(config=u'whatever')
+
+
+if __name__ == '__main__':
+    import unittest
+    unittest.main()