diff -r 9b4de34ad394 -r 97095348b3ee cubicweb/test/unittest_mail.py
--- a/cubicweb/test/unittest_mail.py	Thu Feb 11 21:59:49 2016 +0100
+++ b/cubicweb/test/unittest_mail.py	Wed Feb 17 13:45:34 2016 +0100
@@ -16,19 +16,18 @@
 #
 # 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.mail
-
-"""
+"""unit tests for module cubicweb.mail"""
 
 import os
 import re
+from socket import gethostname
 import sys
+from unittest import TestCase
 
-from logilab.common.testlib import unittest_main
 from logilab.common.umessage import message_from_string
 
 from cubicweb.devtools.testlib import CubicWebTC
-from cubicweb.mail import format_mail
+from cubicweb.mail import format_mail, construct_message_id, parse_message_id
 
 
 def getlogin():
@@ -74,7 +73,6 @@
         self.assertEqual(msg.get('reply-to'), u'oim <oim@logilab.fr>, BimBam <bim@boum.fr>')
         self.assertEqual(msg.get_payload(decode=True), u'un petit cöucou')
 
-
     def test_format_mail_euro(self):
         mail = format_mail({'name': u'oîm', 'email': u'oim@logilab.fr'},
                            ['test@logilab.fr'], u'un petit cöucou €', u'bïjour €')
@@ -99,7 +97,6 @@
         self.assertEqual(msg.get('reply-to'), u'oîm <oim@logilab.fr>')
         self.assertEqual(msg.get_payload(decode=True), u'un petit cöucou €')
 
-
     def test_format_mail_from_reply_to(self):
         # no sender-name, sender-addr in the configuration
         self.set_option('sender-name', '')
@@ -125,18 +122,20 @@
         self.set_option('sender-addr', 'cubicweb-test@logilab.fr')
         # anonymous notification: no name and no email specified
         msg = format_mail({'name': u'', 'email': u''},
-                           ['test@logilab.fr'], u'un petit cöucou €', u'bïjour €',
-                           config=self.config)
+                          ['test@logilab.fr'], u'un petit cöucou €', u'bïjour €',
+                          config=self.config)
         msg = message_from_string(msg.as_string())
         self.assertEqual(msg.get('from'), u'cubicweb-test <cubicweb-test@logilab.fr>')
         self.assertEqual(msg.get('reply-to'), u'cubicweb-test <cubicweb-test@logilab.fr>')
         # anonymous notification: only email specified
         msg = format_mail({'email': u'tutu@logilab.fr'},
-                           ['test@logilab.fr'], u'un petit cöucou €', u'bïjour €',
-                           config=self.config)
+                          ['test@logilab.fr'], u'un petit cöucou €', u'bïjour €',
+                          config=self.config)
         msg = message_from_string(msg.as_string())
         self.assertEqual(msg.get('from'), u'cubicweb-test <tutu@logilab.fr>')
-        self.assertEqual(msg.get('reply-to'), u'cubicweb-test <tutu@logilab.fr>, cubicweb-test <cubicweb-test@logilab.fr>')
+        self.assertEqual(
+            msg.get('reply-to'),
+            u'cubicweb-test <tutu@logilab.fr>, cubicweb-test <cubicweb-test@logilab.fr>')
         # anonymous notification: only name specified
         msg = format_mail({'name': u'tutu'},
                           ['test@logilab.fr'], u'un petit cöucou €', u'bïjour €',
@@ -146,6 +145,41 @@
         self.assertEqual(msg.get('reply-to'), u'tutu <cubicweb-test@logilab.fr>')
 
 
+class MessageIdTC(TestCase):
+
+    def test_base(self):
+        msgid1 = construct_message_id('testapp', 21)
+        msgid2 = construct_message_id('testapp', 21)
+        self.assertNotEqual(msgid1, msgid2)
+        self.assertNotIn('&', msgid1)
+        self.assertNotIn('=', msgid1)
+        self.assertNotIn('/', msgid1)
+        self.assertNotIn('+', msgid1)
+        values = parse_message_id(msgid1, 'testapp')
+        self.assertTrue(values)
+        # parse_message_id should work with or without surrounding <>
+        self.assertEqual(values, parse_message_id(msgid1[1:-1], 'testapp'))
+        self.assertEqual(values['eid'], '21')
+        self.assertIn('timestamp', values)
+        self.assertEqual(parse_message_id(msgid1[1:-1], 'anotherapp'), None)
+
+    def test_notimestamp(self):
+        msgid1 = construct_message_id('testapp', 21, False)
+        construct_message_id('testapp', 21, False)
+        values = parse_message_id(msgid1, 'testapp')
+        self.assertEqual(values, {'eid': '21'})
+
+    def test_parse_message_doesnt_raise(self):
+        self.assertEqual(parse_message_id('oijioj@bla.bla', 'tesapp'), None)
+        self.assertEqual(parse_message_id('oijioj@bla', 'tesapp'), None)
+        self.assertEqual(parse_message_id('oijioj', 'tesapp'), None)
+
+    def test_nonregr_empty_message_id(self):
+        for eid in (1, 12, 123, 1234):
+            msgid1 = construct_message_id('testapp', eid, 12)
+            self.assertNotEqual(msgid1, '<@testapp.%s>' % gethostname())
+
 
 if __name__ == '__main__':
+    from logilab.common.testlib import unittest_main
     unittest_main()