diff --git a/addons/mail/tests/test_mail.py b/addons/mail/tests/test_mail.py
index 7ec37d952bc..10506388da8 100644
--- a/addons/mail/tests/test_mail.py
+++ b/addons/mail/tests/test_mail.py
@@ -505,7 +505,7 @@ class test_mail(TestMailMockups):
 
         # 1. mass_mail on pigs and bird
         compose_id = mail_compose.create(cr, uid,
-            {'subject': _subject, 'body': '${object.description}', 'content_type': 'html'},
+            {'subject': _subject, 'body': '${object.description}'},
             {'default_composition_mode': 'mass_mail', 'default_model': 'mail.group', 'default_res_id': False,
                 'active_ids': [self.group_pigs_id, group_bird_id]})
         compose = mail_compose.browse(cr, uid, compose_id)