[FIX] mass_mailing: fix unsubscription_date when opt_out on create

Before this commit when creating a mailing contact with a mailing
list opt_out at creation the unsubscription_date wasn't set.
Indeed, from the mailing contact view the mailing list uses an
editable list that passes all the values at create even when not set
contrary to when one update the contact only the changed values are
passed. This commit fix this issue.

Task-3070852

closes odoo/odoo#105867

Signed-off-by: Warnon Aurélien (awa) <awa@odoo.com>

addons/mass_mailing/models/mailing_contact.py

@@ -31,7 +31,7 @@ class MassMailingContactListRel(models.Model):
     def create(self, vals_list):
         now = fields.Datetime.now()
         for vals in vals_list:
-            if 'opt_out' in vals and 'unsubscription_date' not in vals:
+            if 'opt_out' in vals and not vals.get('unsubscription_date'):
                 vals['unsubscription_date'] = now if vals['opt_out'] else False
             if vals.get('unsubscription_date'):
                 vals['opt_out'] = True

addons/mass_mailing/tests/test_mailing_list.py

 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from datetime import datetime
+from freezegun import freeze_time
+
 from odoo import exceptions
 from odoo.addons.mass_mailing.tests.common import MassMailCommon
 from odoo.tests.common import Form, users
@@ -99,6 +102,19 @@ class TestMailingListMerge(MassMailCommon):
             new = new.with_context(default_list_ids=[list_id])
             self.assertFalse(any(contact.opt_out for contact in new))
 
+        with freeze_time('2022-01-01 12:00'):
+            contact_form = Form(self.env['mailing.contact'])
+            contact_form.name = 'Contact_test'
+            with contact_form.subscription_list_ids.new() as subscription:
+                subscription.list_id = self.mailing_list_1
+                subscription.opt_out = True
+            with contact_form.subscription_list_ids.new() as subscription:
+                subscription.list_id = self.mailing_list_2
+                subscription.opt_out = False
+            contact = contact_form.save()
+        self.assertEqual(contact.subscription_list_ids[0].unsubscription_date, datetime(2022, 1, 1, 12, 0, 0))
+        self.assertFalse(contact.subscription_list_ids[1].unsubscription_date)
+
     @users('user_marketing')
     def test_mailing_list_contact_copy_in_context_of_mailing_list(self):
         MailingContact = self.env['mailing.contact']