diff -r 058bb3dc685f -r 0b59724cb3f2 cubicweb/server/test/unittest_sqlutils.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/cubicweb/server/test/unittest_sqlutils.py	Sat Jan 16 13:48:51 2016 +0100
@@ -0,0 +1,68 @@
+# -*- coding: utf-8 -*-
+# copyright 2003-2013 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/>.
+"""unit tests for module cubicweb.server.sqlutils
+"""
+
+import sys
+
+from logilab.common.testlib import TestCase, unittest_main
+
+from cubicweb.server.sqlutils import *
+
+from cubicweb.devtools.testlib import CubicWebTC
+
+BASE_CONFIG = {
+    'db-driver' : 'Postgres',
+    'db-host'   : 'crater',
+    'db-name'   : 'cubicweb2_test',
+    'db-user'   : 'toto',
+    'db-upassword' : 'toto',
+    }
+
+class SQLAdapterMixInTC(TestCase):
+
+    def test_init(self):
+        o = SQLAdapterMixIn(BASE_CONFIG)
+        self.assertEqual(o.dbhelper.dbencoding, 'UTF-8')
+
+    def test_init_encoding(self):
+        config = BASE_CONFIG.copy()
+        config['db-encoding'] = 'ISO-8859-1'
+        o = SQLAdapterMixIn(config)
+        self.assertEqual(o.dbhelper.dbencoding, 'ISO-8859-1')
+
+
+class SQLUtilsTC(CubicWebTC):
+
+    def test_group_concat(self):
+        with self.admin_access.repo_cnx() as cnx:
+            g = cnx.create_entity('CWGroup', name=u'héhé')
+            u = cnx.create_entity('CWUser', login=u'toto', upassword=u'',
+                                  in_group=g.eid)
+            rset = cnx.execute(u'Any L,GROUP_CONCAT(G) GROUPBY L WHERE X login L,'
+                               u'X in_group G, G name GN, NOT G name IN ("users", "héhé")')
+            self.assertEqual([[u'admin', u'3'], [u'anon', u'2']],
+                             rset.rows)
+            rset = cnx.execute('Any L,GROUP_CONCAT(GN) GROUPBY L WHERE X login L,'
+                               'X in_group G, G name GN, NOT G name "users"')
+            self.assertEqual([[u'admin', u'managers'], [u'anon', u'guests'], [u'toto', u'héhé']],
+                             rset.rows)
+
+if __name__ == '__main__':
+    unittest_main()