diff --git a/CHANGES b/CHANGES
index e4a3857..e4a15e3 100644
--- a/CHANGES
+++ b/CHANGES
@@ -8,6 +8,7 @@ Tests/
 * new test scripts t_ldap_schema_tokenizer.py and t_ldap_modlist.py
   on former raw scripts
 * new test-cases in t_ldapurl.py based on former raw scripts
+* new test-cases in t_ldap_dn.py
 
 ----------------------------------------------------------------
 Released 2.4.30 2017-02-08
@@ -1327,4 +1328,4 @@ Released 2.0.0pre02 2002-02-01
 ----------------------------------------------------------------
 Released 1.10alpha3 2000-09-19
 
-$Id: CHANGES,v 1.405 2017/02/14 13:37:51 stroeder Exp $
+$Id: CHANGES,v 1.406 2017/02/14 18:02:20 stroeder Exp $
diff --git a/Tests/t_ldap_dn.py b/Tests/t_ldap_dn.py
index 2183d3a..ee47e07 100644
--- a/Tests/t_ldap_dn.py
+++ b/Tests/t_ldap_dn.py
@@ -20,8 +20,17 @@ def test_is_dn(self):
         test function is_dn()
         """
         self.assertEquals(ldap.dn.is_dn('foobar,ou=ae-dir'), False)
+        self.assertEquals(ldap.dn.is_dn('-cn=foobar,ou=ae-dir'), False)
+        self.assertEquals(ldap.dn.is_dn(';cn=foobar,ou=ae-dir'), False)
+        self.assertEquals(ldap.dn.is_dn(',cn=foobar,ou=ae-dir'), False)
+        self.assertEquals(ldap.dn.is_dn('cn=foobar,ou=ae-dir,'), False)
         self.assertEquals(ldap.dn.is_dn('uid=xkcd,cn=foobar,ou=ae-dir'), True)
-
+        self.assertEquals(
+            ldap.dn.is_dn(
+                'cn=\xc3\xa4\xc3\xb6\xc3\xbc\xc3\x84\xc3\x96\xc3\x9c.o=\xc3\xa4\xc3\xb6\xc3\xbc\xc3\x84\xc3\x96\xc3\x9c\xc3\x9f'
+            ),
+            True
+        )
 
 if __name__ == '__main__':
     unittest.main()