diff --git a/addons/mail/tests/common.py b/addons/mail/tests/common.py
index 2fe5f1bcb1b..4277c53892b 100644
--- a/addons/mail/tests/common.py
+++ b/addons/mail/tests/common.py
@@ -11,10 +11,9 @@ from contextlib import contextmanager
 from functools import partial
 from lxml import html
 from unittest.mock import patch
-from smtplib import SMTPServerDisconnected
 
-from odoo import exceptions
-from odoo.addons.base.models.ir_mail_server import IrMailServer, MailDeliveryException
+from odoo.addons.base.models.ir_mail_server import IrMailServer
+from odoo.addons.base.tests.common import MockSmtplibCase
 from odoo.addons.bus.models.bus import ImBus, json_dump
 from odoo.addons.mail.models.mail_mail import MailMail
 from odoo.addons.mail.models.mail_message import Message
@@ -22,10 +21,14 @@ from odoo.addons.mail.models.mail_notification import MailNotification
 from odoo.tests import common, new_test_user
 from odoo.tools import formataddr, pycompat
 
-mail_new_test_user = partial(new_test_user, context={'mail_create_nolog': True, 'mail_create_nosubscribe': True, 'mail_notrack': True, 'no_reset_password': True})
+mail_new_test_user = partial(new_test_user, context={'mail_create_nolog': True,
+                                                     'mail_create_nosubscribe': True,
+                                                     'mail_notrack': True,
+                                                     'no_reset_password': True,
+                                                     'mail_channel_nosubscribe': True})
 
 
-class MockEmail(common.BaseCase):
+class MockEmail(common.BaseCase, MockSmtplibCase):
     """ Tools, helpers and asserts for mailgateway-related tests
 
     Useful reminders
@@ -39,37 +42,19 @@ class MockEmail(common.BaseCase):
     # ------------------------------------------------------------
 
     @contextmanager
-    def mock_mail_gateway(self, mail_unlink_sent=False, sim_error=None):
+    def mock_mail_gateway(self, mail_unlink_sent=False):
         build_email_origin = IrMailServer.build_email
+        send_email_origin = IrMailServer.send_email
         mail_create_origin = MailMail.create
         mail_unlink_origin = MailMail.unlink
         self.mail_unlink_sent = mail_unlink_sent
         self._init_mail_mock()
 
-        def _ir_mail_server_connect(model, *args, **kwargs):
-            if sim_error and sim_error == 'connect_smtp_notfound':
-                raise exceptions.UserError(
-                    "Missing SMTP Server\nPlease define at least one SMTP server, or provide the SMTP parameters explicitly.")
-            if sim_error and sim_error == 'connect_failure':
-                raise Exception("Some exception")
-            return None
-
         def _ir_mail_server_build_email(model, *args, **kwargs):
             self._mails.append(kwargs)
             self._mails_args.append(args)
             return build_email_origin(model, *args, **kwargs)
 
-        def _ir_mail_server_send_email(model, message, *args, **kwargs):
-            if '@' not in message['To']:
-                raise AssertionError(model.NO_VALID_RECIPIENT)
-            if sim_error and sim_error == 'send_assert':
-                raise AssertionError('AssertionError')
-            elif sim_error and sim_error == 'send_disconnect':
-                raise SMTPServerDisconnected('SMTPServerDisconnected')
-            elif sim_error and sim_error == 'send_delivery':
-                raise MailDeliveryException('MailDeliveryException')
-            return message['Message-Id']
-
         def _mail_mail_create(model, *args, **kwargs):
             res = mail_create_origin(model, *args, **kwargs)
             self._new_mails += res.sudo()
@@ -80,11 +65,13 @@ class MockEmail(common.BaseCase):
                 return mail_unlink_origin(model, *args, **kwargs)
             return True
 
-        with patch.object(IrMailServer, 'connect', autospec=True, wraps=IrMailServer, side_effect=_ir_mail_server_connect) as ir_mail_server_connect_mock, \
-                patch.object(IrMailServer, 'build_email', autospec=True, wraps=IrMailServer, side_effect=_ir_mail_server_build_email) as ir_mail_server_build_email_mock, \
-                patch.object(IrMailServer, 'send_email', autospec=True, wraps=IrMailServer, side_effect=_ir_mail_server_send_email) as ir_mail_server_send_email_mock, \
-                patch.object(MailMail, 'create', autospec=True, wraps=MailMail, side_effect=_mail_mail_create) as _mail_mail_create_mock, \
-                patch.object(MailMail, 'unlink', autospec=True, wraps=MailMail, side_effect=_mail_mail_unlink) as mail_mail_unlink_mock:
+        with self.mock_smtplib_connection(), \
+             patch.object(IrMailServer, 'build_email', autospec=True, wraps=IrMailServer, side_effect=_ir_mail_server_build_email) as build_email_mocked, \
+             patch.object(IrMailServer, 'send_email', autospec=True, wraps=IrMailServer, side_effect=send_email_origin) as send_email_mocked, \
+             patch.object(MailMail, 'create', autospec=True, wraps=MailMail, side_effect=_mail_mail_create), \
+             patch.object(MailMail, 'unlink', autospec=True, wraps=MailMail, side_effect=_mail_mail_unlink):
+            self.build_email_mocked = build_email_mocked
+            self.send_email_mocked = send_email_mocked
             yield
 
     def _init_mail_mock(self):
@@ -92,10 +79,6 @@ class MockEmail(common.BaseCase):
         self._mails_args = []
         self._new_mails = self.env['mail.mail'].sudo()
 
-    # ------------------------------------------------------------
-    # GATEWAY TOOLS
-    # ------------------------------------------------------------
-
     @classmethod
     def _init_mail_gateway(cls):
         cls.alias_domain = 'test.com'
@@ -108,6 +91,26 @@ class MockEmail(common.BaseCase):
         cls.env['ir.config_parameter'].set_param('mail.default.from', cls.default_from)
         cls.mailer_daemon_email = formataddr(('MAILER-DAEMON', '%s@%s' % (cls.alias_bounce, cls.alias_domain)))
 
+    @classmethod
+    def _init_outgoing_gateway(cls):
+        cls.env['ir.mail_server'].search([]).unlink()
+        cls.mail_server_domain, cls.mail_server_global = cls.env['ir.mail_server'].create([
+            {'from_filter': 'test.com',
+             'name': 'Domain Based Server',
+             'smtp_encryption': 'none',
+             'smtp_host': 'smtp_host',
+            },
+            {'from_filter': False,
+             'name': 'No FromFilter Server',
+             'smtp_encryption': 'none',
+             'smtp_host': 'smtp_host',
+            }
+        ])
+
+    # ------------------------------------------------------------
+    # GATEWAY TOOLS
+    # ------------------------------------------------------------
+
     def format(self, template, to='groups@example.com, other@gmail.com', subject='Frogs',
                email_from='Sylvie Lelitre <test.sylvie.lelitre@agrolait.com>', return_path='', cc='',
                extra='', msg_id='<1198923581.41972151344608186760.JavaMail@agrolait.com>',
@@ -316,7 +319,7 @@ class MockEmail(common.BaseCase):
     # ------------------------------------------------------------
 
     def assertMailMail(self, recipients, status,
-                       check_mail_mail=True, mail_message=None, author=None,
+                       mail_message=None, author=None,
                        content=None, fields_values=None, email_values=None):
         """ Assert mail.mail records are created and maybe sent as emails. Allow
         asserting their content. Records to check are the one generated when
@@ -335,8 +338,6 @@ class MockEmail(common.BaseCase):
         :param email_values: if given, should be a dictionary of keys / values
           allowing to check sent email additional values (if any).
           See ``assertSentEmail``;
-
-        :param check_mail_mail: deprecated, use ``assertSentEmail`` if False
         """
         found_mail = self._find_mail_mail_wpartners(recipients, status, mail_message=mail_message, author=author)
         self.assertTrue(bool(found_mail))
@@ -370,8 +371,6 @@ class MockEmail(common.BaseCase):
         :param email_values: if given, should be a dictionary of keys / values
           allowing to check sent email additional values (if any).
           See ``assertSentEmail``;
-
-        :param check_mail_mail: deprecated, use ``assertSentEmail`` if False
         """
         for email_to in emails:
             found_mail = self._find_mail_mail_wemail(email_to, status, mail_message=mail_message, author=author)
@@ -410,6 +409,16 @@ class MockEmail(common.BaseCase):
                 found_mail[fname], fvalue,
                 'Mail: expected %s for %s, got %s' % (fvalue, fname, found_mail[fname]))
 
+    def assertMessageFields(self, message, fields_values):
+        """ Just a quick helper to check a mail.message content by giving directly
+        a dict for fields. Allows to hide a lot of assertEqual under a simple
+        call with a dictionary of expected values. """
+        for fname, fvalue in fields_values.items():
+            self.assertEqual(
+                message[fname], fvalue,
+                'Message: expected %s for %s, got %s' % (fvalue, fname, message[fname])
+            )
+
     def assertNoMail(self, recipients, mail_message=None, author=None):
         """ Check no mail.mail and email was generated during gateway mock. """
         try:
@@ -435,8 +444,10 @@ class MockEmail(common.BaseCase):
         :param values: dictionary of additional values to check email content;
         """
         base_expected = {}
-        for fname in ['reply_to', 'subject', 'attachments', 'body', 'references',
-                      'body_content', 'body_alternative_content', 'references_content']:
+        for fname in ['author_id', 'reply_to',
+                      'subject', 'body', 'body_content', 'body_alternative_content',
+                      'references', 'references_content',
+                      'attachments']:
             if fname in values:
                 base_expected[fname] = values[fname]
 
@@ -461,9 +472,14 @@ class MockEmail(common.BaseCase):
         debug_info = '-'.join('From: %s-To: %s' % (mail['email_from'], mail['email_to']) for mail in self._mails) if not bool(sent_mail) else ''
         self.assertTrue(bool(sent_mail), 'Expected mail from %s to %s not found in %s' % (expected['email_from'], expected['email_to'], debug_info))
 
-        for val in ['reply_to', 'subject', 'references', 'attachments']:
+        for val in ['reply_to', 'subject', 'references']:
             if val in expected:
                 self.assertEqual(expected[val], sent_mail[val], 'Value for %s: expected %s, received %s' % (val, expected[val], sent_mail[val]))
+        if 'attachments' in expected:
+            self.assertEqual(
+                sorted(expected['attachments']), sorted(sent_mail['attachments']),
+                'Value for %s: expected %s, received %s' % ('attachments', expected['attachments'], sent_mail['attachments'])
+            )
         if 'attachments_info' in values:
             attachments = sent_mail['attachments']
             for attachment_info in values['attachments_info']:
@@ -473,12 +489,18 @@ class MockEmail(common.BaseCase):
                 if attachment_info.get('type'):
                     self.assertEqual(attachment[2], attachment_info['type'])
             self.assertEqual(len(values['attachments_info']), len(attachments))
-        for val in ['body']:
+        for val in ['body', 'body_alternative']:
             if val in expected:
-                self.assertHtmlEqual(expected[val], sent_mail[val], 'Value for %s: expected %s, received %s' % (val, expected[val], sent_mail[val]))
-        for val in ['body_content', 'body_alternative', 'references_content']:
+                self.assertHtmlEqual(
+                    expected[val], sent_mail[val],
+                    'Value for %s: expected %s, received %s' % (val, expected[val], sent_mail[val])
+                )
+        for val in ['body_content', 'body_alternative_content', 'references_content']:
             if val in expected:
-                self.assertIn(expected[val], sent_mail[val[:-8]], 'Value for %s: %s does not contain %s' % (val, sent_mail[val[:-8]], expected[val]))
+                self.assertIn(
+                    expected[val], sent_mail[val[:-8]],
+                    'Value for %s: %s does not contain %s' % (val, sent_mail[val[:-8]], expected[val])
+                )
 
 
 class MailCase(MockEmail):
@@ -496,10 +518,11 @@ class MailCase(MockEmail):
                             ("UNKNOWN", "Unknown error")
     """
     _test_context = {
+        'mail_channel_nosubscribe': True,
         'mail_create_nolog': True,
         'mail_create_nosubscribe': True,
         'mail_notrack': True,
-        'no_reset_password': True
+        'no_reset_password': True,
     }
 
     @classmethod
@@ -507,7 +530,7 @@ class MailCase(MockEmail):
         return record.with_context(
             mail_create_nolog=False,
             mail_create_nosubscribe=False,
-            mail_notrack=False
+            mail_notrack=False,
         )
 
     def flush_tracking(self):
@@ -627,19 +650,19 @@ class MailCase(MockEmail):
     # ------------------------------------------------------------
 
     @contextmanager
-    def assertSinglePostNotifications(self, recipients_info, message_info=None, mail_unlink_sent=False, sim_error=None):
+    def assertSinglePostNotifications(self, recipients_info, message_info=None, mail_unlink_sent=False):
         """ Shortcut to assertMsgNotifications when having a single message to check. """
         r_info = dict(message_info if message_info else {})
         r_info.setdefault('content', '')
         r_info['notif'] = recipients_info
-        with self.assertPostNotifications([r_info], mail_unlink_sent=mail_unlink_sent, sim_error=sim_error):
+        with self.assertPostNotifications([r_info], mail_unlink_sent=mail_unlink_sent):
             yield
 
     @contextmanager
-    def assertPostNotifications(self, recipients_info, mail_unlink_sent=False, sim_error=None):
+    def assertPostNotifications(self, recipients_info, mail_unlink_sent=False):
         """ Check content of notifications. """
         try:
-            with self.mock_mail_gateway(mail_unlink_sent=mail_unlink_sent, sim_error=sim_error), self.mock_bus(), self.mock_mail_app():
+            with self.mock_mail_gateway(mail_unlink_sent=mail_unlink_sent), self.mock_bus(), self.mock_mail_app():
                 yield
         finally:
             done_msgs, done_notifs = self.assertMailNotifications(self._new_msgs, recipients_info)
@@ -659,7 +682,7 @@ class MailCase(MockEmail):
     @contextmanager
     def assertNoNotifications(self):
         try:
-            with self.mock_mail_gateway(mail_unlink_sent=False, sim_error=None), self.mock_bus(), self.mock_mail_app():
+            with self.mock_mail_gateway(mail_unlink_sent=False), self.mock_bus(), self.mock_mail_app():
                 yield
         finally:
             self.assertFalse(bool(self._new_msgs))
@@ -891,9 +914,14 @@ class MailCommon(common.TransactionCase, MailCase):
         super(MailCommon, cls).setUpClass()
         # give default values for all email aliases and domain
         cls._init_mail_gateway()
+        cls._init_outgoing_gateway()
         # ensure admin configuration
         cls.user_admin = cls.env.ref('base.user_admin')
-        cls.user_admin.write({'notification_type': 'inbox'})
+        cls.user_admin.write({
+            'country_id': cls.env.ref('base.be').id,
+            'email': 'test.admin@test.example.com',
+            'notification_type': 'inbox',
+        })
         cls.partner_admin = cls.env.ref('base.partner_admin')
         cls.company_admin = cls.user_admin.company_id
         cls.company_admin.write({'email': 'company@example.com'})
@@ -905,9 +933,11 @@ class MailCommon(common.TransactionCase, MailCase):
 
         # test standard employee
         cls.user_employee = mail_new_test_user(
-            cls.env, login='employee',
-            groups='base.group_user,mail.group_mail_template_editor',
+            cls.env,
             company_id=cls.company_admin.id,
+            country_id=cls.env.ref('base.be').id,
+            groups='base.group_user,mail.group_mail_template_editor',
+            login='employee',
             name='Ernest Employee',
             notification_type='inbox',
             signature='--\nErnest'
@@ -939,12 +969,26 @@ class MailCommon(common.TransactionCase, MailCase):
             groups='base.group_user',
             company_id=cls.company_2.id,
             company_ids=[(4, cls.company_2.id)],
+            email='enguerrand@example.com',
             name='Enguerrand Employee C2',
             notification_type='inbox',
             signature='--\nEnguerrand'
         )
         cls.partner_employee_c2 = cls.user_employee_c2.partner_id
 
+        # test erp manager employee
+        cls.user_erp_manager = mail_new_test_user(
+            cls.env,
+            company_id=cls.company_2.id,
+            company_ids=[(6, 0, (cls.company_admin + cls.company_2).ids)],
+            email='etchenne@example.com',
+            groups='base.group_user,base.group_erp_manager,mail.group_mail_template_editor',
+            login='erp_manager',
+            name='Etchenne Tchagada',
+            notification_type='inbox',
+            signature='--\nEtchenne',
+        )
+
     @classmethod
     def _activate_multi_lang(cls, lang_code='es_ES', layout_arch_db=None, test_record=False, test_template=False):
         """ Summary of es_ES matching done here (a bit hardcoded to ease tests)
@@ -1097,15 +1141,18 @@ class MailCommon(common.TransactionCase, MailCase):
         })
         cls.env['ir.translation'].create(translations_tocreate)
 
-    def _generate_attachments_data(self, count, res_model=None, res_id=None):
+    def _generate_attachments_data(self, count, res_model=None, res_id=None, attach_values=None):
         # attachment visibility depends on what they are attached to
+        attach_values = attach_values or {}
         if res_model is None:
             res_model = self.template._name
         if res_id is None:
             res_id = self.template.id
         return [{
-            'name': '%02d.txt' % x,
-            'datas': base64.b64encode(b'Att%02d' % x),
+            'datas': base64.b64encode(b'AttContent_%02d' % x),
+            'name': 'AttFileName_%02d.txt' % x,
+            'mimetype': 'text/plain',
             'res_model': res_model,
             'res_id': res_id,
+            **attach_values,
         } for x in range(count)]
diff --git a/addons/mail/tests/test_mail_channel_partner.py b/addons/mail/tests/test_mail_channel_partner.py
index 8f6e8a66424..f7ba426648f 100644
--- a/addons/mail/tests/test_mail_channel_partner.py
+++ b/addons/mail/tests/test_mail_channel_partner.py
@@ -1,10 +1,14 @@
 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
+from functools import partial
+
 from odoo.addons.mail.tests.common import mail_new_test_user
 from odoo.addons.mail.tests.common import MailCommon
 from odoo.exceptions import AccessError, UserError
 
+mail_channel_new_test_user = partial(mail_new_test_user, context={'mail_channel_nosubscribe': False})
+
 
 class TestMailChannelMembers(MailCommon):
 
@@ -22,23 +26,23 @@ class TestMailChannelMembers(MailCommon):
             'res_id': cls.secret_group.id,
         })
 
-        cls.user_1 = mail_new_test_user(
+        cls.user_1 = mail_channel_new_test_user(
             cls.env, login='user_1',
             name='User 1',
             groups='base.group_user,mail.secret_group')
-        cls.user_2 = mail_new_test_user(
+        cls.user_2 = mail_channel_new_test_user(
             cls.env, login='user_2',
             name='User 2',
             groups='base.group_user,mail.secret_group')
-        cls.user_3 = mail_new_test_user(
+        cls.user_3 = mail_channel_new_test_user(
             cls.env, login='user_3',
             name='User 3',
             groups='base.group_user,mail.secret_group')
-        cls.user_portal = mail_new_test_user(
+        cls.user_portal = mail_channel_new_test_user(
             cls.env, login='user_portal',
             name='User Portal',
             groups='base.group_portal')
-        cls.user_public = mail_new_test_user(
+        cls.user_public = mail_channel_new_test_user(
             cls.env, login='user_ublic',
             name='User Public',
             groups='base.group_public')
diff --git a/addons/test_mail/tests/common.py b/addons/test_mail/tests/common.py
index ae43c3ae437..88759108d48 100644
--- a/addons/test_mail/tests/common.py
+++ b/addons/test_mail/tests/common.py
@@ -9,27 +9,29 @@ class TestMailCommon(MailCommon):
     """ Main entry point for functional tests. """
 
     @classmethod
-    def _create_channel_listener(cls):
-        cls.channel_listen = cls.env['mail.channel'].with_context(cls._test_context).create({'name': 'Listener'})
-
-    @classmethod
-    def _create_records_for_batch(cls, model, count):
-        # TDE note: to be cleaned in master
+    def _create_records_for_batch(cls, model, count, additional_values=None):
+        additional_values = additional_values or {}
         records = cls.env[model]
         partners = cls.env['res.partner']
         country_id = cls.env.ref('base.be').id
 
-        partners = cls.env['res.partner'].with_context(**cls._test_context).create([{
-            'name': 'Partner_%s' % (x),
-            'email': '_test_partner_%s@example.com' % (x),
-            'country_id': country_id,
-            'mobile': '047500%02d%02d' % (x, x)
-        } for x in range(count)])
+        base_values = [
+            {'name': 'Test_%s' % idx,
+             **additional_values,
+            } for idx in range(count)
+        ]
 
-        records = cls.env[model].with_context(**cls._test_context).create([{
-            'name': 'Test_%s' % (x),
-            'customer_id': partners[x].id,
-        } for x in range(count)])
+        if 'customer_id' in cls.env[model]:
+            partners = cls.env['res.partner'].with_context(**cls._test_context).create([{
+                'name': 'Partner_%s' % idx,
+                'email': '_test_partner_%s@example.com' % idx,
+                'country_id': country_id,
+                'mobile': '047500%02d%02d' % (idx, idx)
+            } for idx in range(count)])
+            for values, partner in zip(base_values, partners):
+                values['customer_id'] = partner.id
+
+        records = cls.env[model].with_context(**cls._test_context).create(base_values)
 
         cls.records = cls._reset_mail_context(records)
         cls.partners = partners
diff --git a/addons/test_mail/tests/test_mail_composer.py b/addons/test_mail/tests/test_mail_composer.py
index 01c6587ae17..57f4adfbadd 100644
--- a/addons/test_mail/tests/test_mail_composer.py
+++ b/addons/test_mail/tests/test_mail_composer.py
@@ -18,7 +18,6 @@ class TestMailComposer(TestMailCommon, TestRecipients):
     @classmethod
     def setUpClass(cls):
         super(TestMailComposer, cls).setUpClass()
-        cls._init_mail_gateway()
 
         # ensure employee can create partners, necessary for templates
         cls.user_employee.write({
@@ -609,8 +608,8 @@ class TestComposerResultsComment(TestMailComposer):
                                 'email_from': self.test_record.user_id.email_formatted,  # set by template
                                 'subject': 'TemplateSubject %s' % self.test_record.name,
                                 'attachments_info': [
-                                    {'name': '00.txt', 'raw': b'Att00', 'type': 'text/plain'},
-                                    {'name': '01.txt', 'raw': b'Att01', 'type': 'text/plain'},
+                                    {'name': 'AttFileName_00.txt', 'raw': b'AttContent_00', 'type': 'text/plain'},
+                                    {'name': 'AttFileName_01.txt', 'raw': b'AttContent_01', 'type': 'text/plain'},
                                     {'name': 'TestReport for %s.html' % self.test_record.name, 'type': 'text/plain'},
                                 ]
                             },
@@ -624,8 +623,8 @@ class TestComposerResultsComment(TestMailComposer):
                                 'email_from': self.test_record.user_id.email_formatted,  # set by template
                                 'subject': 'TemplateSubject %s' % self.test_record.name,
                                 'attachments_info': [
-                                    {'name': '00.txt', 'raw': b'Att00', 'type': 'text/plain'},
-                                    {'name': '01.txt', 'raw': b'Att01', 'type': 'text/plain'},
+                                    {'name': 'AttFileName_00.txt', 'raw': b'AttContent_00', 'type': 'text/plain'},
+                                    {'name': 'AttFileName_01.txt', 'raw': b'AttContent_01', 'type': 'text/plain'},
                                     {'name': 'TestReport for %s.html' % self.test_record.name, 'type': 'text/plain'},
                                 ]
                             },
@@ -638,7 +637,7 @@ class TestComposerResultsComment(TestMailComposer):
         # attachments are copied on message and linked to document
         self.assertEqual(
             set(message.attachment_ids.mapped('name')),
-            set(['00.txt', '01.txt', 'TestReport for %s.html' % self.test_record.name])
+            set(['AttFileName_00.txt', 'AttFileName_01.txt', 'TestReport for %s.html' % self.test_record.name])
         )
         self.assertEqual(set(message.attachment_ids.mapped('res_model')), set([self.test_record._name]))
         self.assertEqual(set(message.attachment_ids.mapped('res_id')), set(self.test_record.ids))
diff --git a/addons/test_mail/tests/test_mail_composer_mixin.py b/addons/test_mail/tests/test_mail_composer_mixin.py
index d13473f7801..5b85c34ed5c 100644
--- a/addons/test_mail/tests/test_mail_composer_mixin.py
+++ b/addons/test_mail/tests/test_mail_composer_mixin.py
@@ -12,7 +12,6 @@ class TestMailComposerMixin(TestMailCommon, TestRecipients):
     @classmethod
     def setUpClass(cls):
         super(TestMailComposerMixin, cls).setUpClass()
-        cls._init_mail_gateway()
 
         cls.mail_template = cls.env['mail.template'].create({
             'subject': 'Subject for {{ object.name }}',
diff --git a/addons/test_mail/tests/test_mail_followers.py b/addons/test_mail/tests/test_mail_followers.py
index 8e6a54c0501..4a1e0d94258 100644
--- a/addons/test_mail/tests/test_mail_followers.py
+++ b/addons/test_mail/tests/test_mail_followers.py
@@ -14,7 +14,6 @@ class BaseFollowersTest(TestMailCommon):
         super(BaseFollowersTest, cls).setUpClass()
         cls.test_record = cls.env['mail.test.simple'].with_context(cls._test_context).create({'name': 'Test', 'email_from': 'ignasse@example.com'})
         cls._create_portal_user()
-        cls._create_channel_listener()
 
         # allow employee to update partners
         cls.user_employee.write({'groups_id': [(4, cls.env.ref('base.group_partner_manager').id)]})
diff --git a/addons/test_mail/tests/test_mail_gateway.py b/addons/test_mail/tests/test_mail_gateway.py
index aff9f63bf71..d5e1e669325 100644
--- a/addons/test_mail/tests/test_mail_gateway.py
+++ b/addons/test_mail/tests/test_mail_gateway.py
@@ -247,8 +247,6 @@ class TestMailgateway(TestMailCommon):
             'message_id': '<123456-openerp-%s-mail.test.gateway@%s>' % (cls.test_record.id, socket.gethostname()),
         })
 
-        cls._init_mail_gateway()
-
     # --------------------------------------------------
     # Base low-level tests
     # --------------------------------------------------
@@ -1277,8 +1275,6 @@ class TestMailThreadCC(TestMailCommon):
             'alias_model_id': cls.env['ir.model']._get('mail.test.cc').id,
             'alias_contact': 'everyone'})
 
-        cls._init_mail_gateway()
-
     @mute_logger('odoo.addons.mail.models.mail_thread')
     def test_message_cc_new(self):
         record = self.format_and_process(MAIL_TEMPLATE, self.email_from, 'cc_record@test.com',
diff --git a/addons/test_mail/tests/test_mail_mail.py b/addons/test_mail/tests/test_mail_mail.py
index 04f48e1a992..0f587e54c02 100644
--- a/addons/test_mail/tests/test_mail_mail.py
+++ b/addons/test_mail/tests/test_mail_mail.py
@@ -5,19 +5,17 @@ import psycopg2
 from unittest.mock import call
 
 from odoo import api
-from odoo.addons.base.tests.common import MockSmtplibCase
 from odoo.addons.test_mail.tests.common import TestMailCommon
 from odoo.tests import common, tagged
 from odoo.tools import mute_logger
 
 
 @tagged('mail_mail')
-class TestMailMail(TestMailCommon, MockSmtplibCase):
+class TestMailMail(TestMailCommon):
 
     @classmethod
     def setUpClass(cls):
         super(TestMailMail, cls).setUpClass()
-        cls._init_mail_gateway()
         cls._init_mail_servers()
 
         cls.server_domain_2 = cls.env['ir.mail_server'].create({
@@ -133,6 +131,7 @@ class TestMailMail(TestMailCommon, MockSmtplibCase):
         self.assert_email_sent_smtp(message_from='user_1@test_2.com', emails_count=5, from_filter=self.server_domain.from_filter)
 
 
+@tagged('mail_mail')
 class TestMailMailRace(common.TransactionCase):
 
     @mute_logger('odoo.addons.mail.models.mail_mail')
diff --git a/addons/test_mail/tests/test_mail_message.py b/addons/test_mail/tests/test_mail_message.py
index f4bfe292a68..0ebbc5e9f05 100644
--- a/addons/test_mail/tests/test_mail_message.py
+++ b/addons/test_mail/tests/test_mail_message.py
@@ -18,7 +18,6 @@ class TestMessageValues(TestMailCommon):
     def setUpClass(cls):
         super(TestMessageValues, cls).setUpClass()
 
-        cls._init_mail_gateway()
         cls.alias_record = cls.env['mail.test.container'].with_context(cls._test_context).create({
             'name': 'Pigs',
             'alias_name': 'pigs',
diff --git a/addons/test_mail/tests/test_mail_multicompany.py b/addons/test_mail/tests/test_mail_multicompany.py
index 18082651e69..58309a7482f 100644
--- a/addons/test_mail/tests/test_mail_multicompany.py
+++ b/addons/test_mail/tests/test_mail_multicompany.py
@@ -47,8 +47,6 @@ class TestMultiCompanySetup(TestMailCommon, TestRecipients):
             'message_id': '<123456-openerp-%s-mail.test.gateway@%s>' % (cls.test_record.id, socket.gethostname()),
         })
 
-        cls._init_mail_gateway()
-
     @users('employee')
     def test_notify_reply_to_computation(self):
         test_record = self.env['mail.test.gateway'].browse(self.test_record.ids)
diff --git a/addons/test_mail/tests/test_mail_thread_internals.py b/addons/test_mail/tests/test_mail_thread_internals.py
index 58c7a0b2538..56b9258070a 100644
--- a/addons/test_mail/tests/test_mail_thread_internals.py
+++ b/addons/test_mail/tests/test_mail_thread_internals.py
@@ -103,6 +103,7 @@ class TestChatterTweaks(TestMailCommon, TestRecipients):
         self.assertTrue(record.name)
 
 
+@tagged('mail_thread')
 class TestDiscuss(TestMailCommon, TestRecipients):
 
     @classmethod
@@ -239,7 +240,12 @@ class TestDiscuss(TestMailCommon, TestRecipients):
             partner_ids=[self.user_employee.partner_id.id]
         )
         self.assertFalse(message.has_error)
-        with self.mock_mail_gateway(sim_error='connect_smtp_notfound'):
+
+        with self.mock_mail_gateway():
+            def _connect(*args, **kwargs):
+                raise Exception("Some exception")
+            self.connect_mocked.side_effect = _connect
+
             self.user_admin.notification_type = 'email'
             message2 = self.test_record.with_user(self.user_employee).message_post(
                 body='Test', message_type='comment', subtype_xmlid='mail.mt_comment',
diff --git a/addons/test_mail/tests/test_message_management.py b/addons/test_mail/tests/test_message_management.py
index 57d24e47f92..e1e5ab203e9 100644
--- a/addons/test_mail/tests/test_message_management.py
+++ b/addons/test_mail/tests/test_message_management.py
@@ -34,8 +34,10 @@ class TestMailResend(TestMailCommon):
     def test_mail_resend_workflow(self):
         with self.assertSinglePostNotifications(
                 [{'partner': partner, 'type': 'email', 'status': 'exception'} for partner in self.partners],
-                message_info={'message_type': 'notification'},
-                sim_error='connect_failure'):
+                message_info={'message_type': 'notification'}):
+            def _connect(*args, **kwargs):
+                raise Exception("Some exception")
+            self.connect_mocked.side_effect = _connect
             message = self.test_record.with_user(self.user_admin).message_post(partner_ids=self.partners.ids, subtype_xmlid='mail.mt_comment', message_type='notification')
 
         wizard = self.env['mail.resend.message'].with_context({'mail_message_to_resend': message.id}).create({})
diff --git a/addons/test_mail/tests/test_performance.py b/addons/test_mail/tests/test_performance.py
index 29a014a18a2..a6076f63606 100644
--- a/addons/test_mail/tests/test_performance.py
+++ b/addons/test_mail/tests/test_performance.py
@@ -48,6 +48,7 @@ class BaseMailPerformance(TransactionCaseWithUserDemo):
         # patch registry to simulate a ready environment
         self.patch(self.env.registry, 'ready', True)
         self._flush_tracking()
+        self._init_mail_gateway()
 
     def _init_mail_gateway(self):
         # setup mail gateway
@@ -113,8 +114,6 @@ class TestBaseMailPerformance(BaseMailPerformance):
             }
         ])
 
-        self._init_mail_gateway()
-
     @users('__system__', 'demo')
     @warmup
     def test_read_mail(self):
@@ -223,8 +222,6 @@ class TestMailAPIPerformance(BaseMailPerformance):
             'groups_id': [(6, 0, [self.env.ref('base.group_user').id])],
         })
 
-        self._init_mail_gateway()
-
         # automatically follow activities, for backward compatibility concerning query count
         self.env.ref('mail.mt_activities').write({'default': True})
 
@@ -531,10 +528,8 @@ class TestMailComplexPerformance(BaseMailPerformance):
             self.partners |= Partners.create({'name': 'Test %s' % x, 'email': 'test%s@example.com' % x})
         self.container.message_subscribe(self.partners.ids, subtype_ids=[
             self.env.ref('mail.mt_comment').id,
-            self.env.ref('test_mail.st_mail_test_container_child_full').id]
-        )
-
-        self._init_mail_gateway()
+            self.env.ref('test_mail.st_mail_test_container_child_full').id
+        ])
 
         # `test_complex_mail_mail_send`
         self.container.flush()
@@ -991,8 +986,6 @@ class TestMailHeavyPerformancePost(BaseMailPerformance):
             'res_id': 0,
         } for i in range(3)]
 
-        self._init_mail_gateway()
-
     @mute_logger('odoo.tests', 'odoo.addons.mail.models.mail_mail', 'odoo.models.unlink')
     @users('employee')
     @warmup
diff --git a/addons/test_mail_full/tests/test_sms_performance.py b/addons/test_mail_full/tests/test_sms_performance.py
index 24108442039..1e63a832f0c 100644
--- a/addons/test_mail_full/tests/test_sms_performance.py
+++ b/addons/test_mail_full/tests/test_sms_performance.py
@@ -29,8 +29,6 @@ class TestSMSPerformance(BaseMailPerformance, sms_common.SMSCase):
             } for x in range(0, 10)
         ])
 
-        self._init_mail_gateway()
-
     @mute_logger('odoo.addons.sms.models.sms_sms')
     @users('employee')
     @warmup
diff --git a/addons/test_mass_mailing/tests/test_mailing_server.py b/addons/test_mass_mailing/tests/test_mailing_server.py
index 0bc1d35c222..53986f491a5 100644
--- a/addons/test_mass_mailing/tests/test_mailing_server.py
+++ b/addons/test_mass_mailing/tests/test_mailing_server.py
@@ -2,20 +2,17 @@
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
 from odoo.addons.test_mass_mailing.tests.common import TestMassMailCommon
-from odoo.addons.base.tests.common import MockSmtplibCase
 from odoo.tests import tagged
 from odoo.tests.common import users
 from odoo.tools import mute_logger
 
 
 @tagged('mass_mailing')
-class TestMassMailingServer(TestMassMailCommon, MockSmtplibCase):
+class TestMassMailingServer(TestMassMailCommon):
 
     @classmethod
     def setUpClass(cls):
         super(TestMassMailingServer, cls).setUpClass()
-        cls._init_mail_gateway()
-        cls.env['ir.mail_server'].search([]).unlink()
         cls._init_mail_servers()
         cls.recipients = cls._create_mailing_test_records(model='mailing.test.optout', count=8)
 
diff --git a/odoo/addons/base/tests/common.py b/odoo/addons/base/tests/common.py
index 0fd845209db..28ddff19b06 100644
--- a/odoo/addons/base/tests/common.py
+++ b/odoo/addons/base/tests/common.py
@@ -252,14 +252,14 @@ class MockSmtplibCase:
         self.testing_smtp_session = TestingSMTPSession()
 
         IrMailServer = self.env['ir.mail_server']
-        connect = IrMailServer.connect
-        find_mail_server = IrMailServer._find_mail_server
+        connect_origin = IrMailServer.connect
+        find_mail_server_origin = IrMailServer._find_mail_server
 
-        with patch.object(type(IrMailServer), '_is_test_mode', lambda self: False), \
-             patch('smtplib.SMTP_SSL', side_effect=lambda *args, **kwargs: self.testing_smtp_session), \
+        with patch('smtplib.SMTP_SSL', side_effect=lambda *args, **kwargs: self.testing_smtp_session), \
              patch('smtplib.SMTP', side_effect=lambda *args, **kwargs: self.testing_smtp_session), \
-             patch.object(type(IrMailServer), 'connect', side_effect=connect) as connect_mocked, \
-             patch.object(type(IrMailServer), '_find_mail_server', side_effect=find_mail_server) as find_mail_server_mocked:
+             patch.object(type(IrMailServer), '_is_test_mode', lambda self: False), \
+             patch.object(type(IrMailServer), 'connect', wraps=IrMailServer, side_effect=connect_origin) as connect_mocked, \
+             patch.object(type(IrMailServer), '_find_mail_server', side_effect=find_mail_server_origin) as find_mail_server_mocked:
             self.connect_mocked = connect_mocked
             self.find_mail_server_mocked = find_mail_server_mocked
             yield
@@ -298,14 +298,16 @@ class MockSmtplibCase:
         )
 
     @classmethod
-    def _init_mail_servers(cls):
-        cls.env['ir.config_parameter'].sudo().set_param('mail.catchall.domain', 'test.com')
-        cls.env['ir.config_parameter'].sudo().set_param('mail.default.from', 'notifications')
-        cls.env['ir.config_parameter'].sudo().set_param('mail.bounce.alias', 'bounce')
-
-        cls.alias_bounce = 'bounce'
+    def _init_mail_config(cls):
+        cls.alias_bounce = 'bounce.test'
         cls.alias_domain = 'test.com'
+        cls.default_from = 'notifications'
+        cls.env['ir.config_parameter'].sudo().set_param('mail.catchall.domain', cls.alias_domain)
+        cls.env['ir.config_parameter'].sudo().set_param('mail.default.from', cls.default_from)
+        cls.env['ir.config_parameter'].sudo().set_param('mail.bounce.alias', cls.alias_bounce)
 
+    @classmethod
+    def _init_mail_servers(cls):
         cls.env['ir.mail_server'].search([]).unlink()
 
         ir_mail_server_values = {
diff --git a/odoo/addons/base/tests/test_ir_mail_server.py b/odoo/addons/base/tests/test_ir_mail_server.py
index 448f04c2d06..c2a330067f9 100644
--- a/odoo/addons/base/tests/test_ir_mail_server.py
+++ b/odoo/addons/base/tests/test_ir_mail_server.py
@@ -15,6 +15,7 @@ from odoo.tools import mute_logger
 class TestIrMailServer(TransactionCase, MockSmtplibCase):
 
     def setUp(self):
+        self._init_mail_config()
         self._init_mail_servers()
 
     def _build_email(self, mail_from, return_path=None):
@@ -231,7 +232,7 @@ class TestIrMailServer(TransactionCase, MockSmtplibCase):
         self.assertEqual(len(self.emails), 1)
 
         self.assert_email_sent_smtp(
-            smtp_from='bounce@xn--9caaaaaaa.com',
+            smtp_from='bounce.test@xn--9caaaaaaa.com',
             smtp_to_list=['dest@xn--example--i1a.com'],
             message_from='test@=?utf-8?b?w6nDqcOpw6nDqcOpw6k=?=.com',
             from_filter=False,
@@ -322,7 +323,7 @@ class TestIrMailServer(TransactionCase, MockSmtplibCase):
         )
 
     @mute_logger('odoo.models.unlink')
-    @patch.dict("odoo.tools.config.options", {"from_filter": "test.com"})
+    @patch.dict("odoo.tools.config.options", {"from_filter": "test.com", "smtp_server": "example.com"})
     def test_mail_server_binary_arguments_domain(self):
         """Test the configuration provided in the odoo-bin arguments.
 
@@ -374,7 +375,7 @@ class TestIrMailServer(TransactionCase, MockSmtplibCase):
         )
 
     @mute_logger('odoo.models.unlink')
-    @patch.dict("odoo.tools.config.options", {"from_filter": "test.com"})
+    @patch.dict("odoo.tools.config.options", {"from_filter": "test.com", "smtp_server": "example.com"})
     def test_mail_server_binary_arguments_domain_smtp_session(self):
         """Test the configuration provided in the odoo-bin arguments.
 
@@ -417,7 +418,7 @@ class TestIrMailServer(TransactionCase, MockSmtplibCase):
         )
 
     @mute_logger('odoo.models.unlink')
-    @patch.dict('odoo.tools.config.options', {'from_filter': 'test.com'})
+    @patch.dict('odoo.tools.config.options', {'from_filter': 'test.com', 'smtp_server': 'example.com'})
     def test_mail_server_mail_default_from_filter(self):
         """Test that the config parameter "mail.default.from_filter" overwrite the odoo-bin
         argument "--from-filter"