diff --git a/ChangeLog b/ChangeLog
index 9f17778..e5980ff 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri Jul 24 18:03:59 2015 +0200 Emmanuel Garette <egarette@cadoles.com>
+	* add duplicate option to Config, to generate new Config with same
+	value, properties, Option. Option are not duplication.
+
 Mon Apr 20 14:44:15 2015 +0200 Emmanuel Garette <egarette@cadoles.com>
 	* if option is multi, the properties disallow [None] for a multi but
 	[] too, with allow_empty_list to True, [None] is not allowed, but you
diff --git a/test/test_duplicate_config.py b/test/test_duplicate_config.py
new file mode 100644
index 0000000..d4b65d9
--- /dev/null
+++ b/test/test_duplicate_config.py
@@ -0,0 +1,56 @@
+# coding: utf-8
+from autopath import do_autopath
+do_autopath()
+
+from tiramisu.setting import groups
+from tiramisu.config import Config
+from tiramisu.option import ChoiceOption, BoolOption, IntOption, \
+    StrOption, OptionDescription
+from test.test_state import _diff_opts, _diff_conf
+from py.test import raises
+
+
+def make_description():
+    numero_etab = StrOption('numero_etab', "identifiant de l'établissement")
+    nom_machine = StrOption('nom_machine', "nom de la machine", default="eoleng")
+    nombre_interfaces = IntOption('nombre_interfaces', "nombre d'interfaces à activer",
+                                  default=1)
+    activer_proxy_client = BoolOption('activer_proxy_client', "utiliser un proxy",
+                                      default=False)
+    mode_conteneur_actif = BoolOption('mode_conteneur_actif', "le serveur est en mode conteneur",
+                                      default=False)
+    mode_conteneur_actif2 = BoolOption('mode_conteneur_actif2', "le serveur est en mode conteneur2",
+                                       default=False, properties=('hidden',))
+
+    adresse_serveur_ntp = StrOption('serveur_ntp', "adresse serveur ntp", multi=True)
+    time_zone = ChoiceOption('time_zone', 'fuseau horaire du serveur',
+                             ('Paris', 'Londres'), 'Paris')
+
+    ip_admin_eth0 = StrOption('ip_admin_eth0', "ip réseau autorisé")
+    netmask_admin_eth0 = StrOption('netmask_admin_eth0', "masque du sous-réseau")
+
+    master = OptionDescription('ip_admin_eth0', '', [ip_admin_eth0, netmask_admin_eth0])
+    interface1 = OptionDescription('interface1', '', [master])
+    interface1.impl_set_group_type(groups.family)
+
+    general = OptionDescription('general', '', [numero_etab, nom_machine,
+                                nombre_interfaces, activer_proxy_client,
+                                mode_conteneur_actif, mode_conteneur_actif2,
+                                adresse_serveur_ntp, time_zone])
+    general.impl_set_group_type(groups.family)
+    new = OptionDescription('new', '', [], properties=('hidden',))
+    new.impl_set_group_type(groups.family)
+    creole = OptionDescription('creole', 'first tiramisu configuration', [general, interface1, new])
+    descr = OptionDescription('baseconfig', 'baseconifgdescr', [creole])
+    return descr
+
+
+def test_duplicate():
+    cfg = Config(make_description())
+    ncfg = cfg.duplicate()
+    _diff_opts(cfg.cfgimpl_get_description(), ncfg.cfgimpl_get_description())
+    _diff_conf(cfg, ncfg)
+    cfg.creole.general.numero_etab = 'oui'
+    raises(AssertionError, "_diff_conf(cfg, ncfg)")
+    ncfg.creole.general.numero_etab = 'oui'
+    _diff_conf(cfg, ncfg)