[IMP] running speed of some tests & new testcase type

Some tests (e.g. mail) have expensive and significant DB setup for a
number of small and cheap tests. Using a TransactionCase, the DB setup
far dominates the tests themselves, by up to 10x (mail unit tests take
~130s on my machine, the tests themselves take ~15s).

The SavepointCase introduced here is an hybrid of SingleTransactionCase
and TransactionCase: it uses a single transaction for all tests in a
class, but each test case is isolated by a rollbacked savepoint. This
allows a common DB setup (via setUpClass) while keeping independent
tests.

TransactionCase should remain the primary test case superclass, but
SavepointCase can be a fair optimisation when setup costs far dominate.

addons/mail/tests/common.py

@@ -22,63 +22,66 @@
 from openerp.tests import common
 
 
-class TestMail(common.TransactionCase):
+class TestMail(common.SavepointCase):
 
-    def _init_mock_build_email(self):
+    @classmethod
-        self._build_email_args_list = []
+    def _init_mock_build_email(cls):
-        self._build_email_kwargs_list = []
+        cls._build_email_args_list = []
+        cls._build_email_kwargs_list = []
 
     def setUp(self):
         super(TestMail, self).setUp()
-        cr, uid = self.cr, self.uid
+        self._build_email_args_list[:] = []
+        self._build_email_kwargs_list[:] = []
 
-        # Install mock SMTP gateway
+    @classmethod
-        test = self
+    def setUpClass(cls):
+        super(TestMail, cls).setUpClass()
+        cr, uid = cls.cr, cls.uid
 
         def build_email(self, *args, **kwargs):
-            test._build_email_args_list.append(args)
+            cls._build_email_args_list.append(args)
-            test._build_email_kwargs_list.append(kwargs)
+            cls._build_email_kwargs_list.append(kwargs)
             return build_email.origin(self, *args, **kwargs)
 
         def send_email(self, cr, uid, message, *args, **kwargs):
             return message['Message-Id']
 
-        self._init_mock_build_email()
+        cls._init_mock_build_email()
-        self.registry('ir.mail_server')._patch_method('build_email', build_email)
+        cls.registry('ir.mail_server')._patch_method('build_email', build_email)
-        self.registry('ir.mail_server')._patch_method('send_email', send_email)
+        cls.registry('ir.mail_server')._patch_method('send_email', send_email)
 
         # Usefull models
-        self.ir_model = self.registry('ir.model')
+        cls.ir_model = cls.registry('ir.model')
-        self.ir_model_data = self.registry('ir.model.data')
+        cls.ir_model_data = cls.registry('ir.model.data')
-        self.ir_attachment = self.registry('ir.attachment')
+        cls.ir_attachment = cls.registry('ir.attachment')
-        self.mail_alias = self.registry('mail.alias')
+        cls.mail_alias = cls.registry('mail.alias')
-        self.mail_thread = self.registry('mail.thread')
+        cls.mail_thread = cls.registry('mail.thread')
-        self.mail_group = self.registry('mail.group')
+        cls.mail_group = cls.registry('mail.group')
-        self.mail_mail = self.registry('mail.mail')
+        cls.mail_mail = cls.registry('mail.mail')
-        self.mail_message = self.registry('mail.message')
+        cls.mail_message = cls.registry('mail.message')
-        self.mail_notification = self.registry('mail.notification')
+        cls.mail_notification = cls.registry('mail.notification')
-        self.mail_followers = self.registry('mail.followers')
+        cls.mail_followers = cls.registry('mail.followers')
-        self.mail_message_subtype = self.registry('mail.message.subtype')
+        cls.mail_message_subtype = cls.registry('mail.message.subtype')
-        self.res_users = self.registry('res.users')
+        cls.res_users = cls.registry('res.users')
-        self.res_partner = self.registry('res.partner')
+        cls.res_partner = cls.registry('res.partner')
 
         # Find Employee group
-        group_employee_ref = self.registry('ir.model.data').get_object_reference(cr, uid, 'base', 'group_user')
+        cls.group_employee_id = cls.env.ref('base.group_user').id or False
-        self.group_employee_id = group_employee_ref and group_employee_ref[1] or False
 
         # Partner Data
 
         # User Data: employee, noone
-        self.user_employee_id = self.res_users.create(cr, uid, {
+        cls.user_employee_id = cls.res_users.create(cr, uid, {
             'name': 'Ernest Employee',
             'login': 'ernest',
             'alias_name': 'ernest',
             'email': 'e.e@example.com',
             'signature': '--\nErnest',
             'notify_email': 'always',
-            'groups_id': [(6, 0, [self.group_employee_id])]
+            'groups_id': [(6, 0, [cls.group_employee_id])]
         }, {'no_reset_password': True})
-        self.user_noone_id = self.res_users.create(cr, uid, {
+        cls.user_noone_id = cls.res_users.create(cr, uid, {
             'name': 'Noemie NoOne',
             'login': 'noemie',
             'alias_name': 'noemie',
@@ -89,16 +92,16 @@ class TestMail(common.TransactionCase):
         }, {'no_reset_password': True})
 
         # Test users to use through the various tests
-        self.res_users.write(cr, uid, uid, {'name': 'Administrator'})
+        cls.res_users.write(cr, uid, uid, {'name': 'Administrator'})
-        self.user_raoul_id = self.res_users.create(cr, uid, {
+        cls.user_raoul_id = cls.res_users.create(cr, uid, {
             'name': 'Raoul Grosbedon',
             'signature': 'SignRaoul',
             'email': 'raoul@raoul.fr',
             'login': 'raoul',
             'alias_name': 'raoul',
-            'groups_id': [(6, 0, [self.group_employee_id])]
+            'groups_id': [(6, 0, [cls.group_employee_id])]
         })
-        self.user_bert_id = self.res_users.create(cr, uid, {
+        cls.user_bert_id = cls.res_users.create(cr, uid, {
             'name': 'Bert Tartignole',
             'signature': 'SignBert',
             'email': 'bert@bert.fr',
@@ -106,27 +109,28 @@ class TestMail(common.TransactionCase):
             'alias_name': 'bert',
             'groups_id': [(6, 0, [])]
         })
-        self.user_raoul = self.res_users.browse(cr, uid, self.user_raoul_id)
+        cls.user_raoul = cls.res_users.browse(cr, uid, cls.user_raoul_id)
-        self.user_bert = self.res_users.browse(cr, uid, self.user_bert_id)
+        cls.user_bert = cls.res_users.browse(cr, uid, cls.user_bert_id)
-        self.user_admin = self.res_users.browse(cr, uid, uid)
+        cls.user_admin = cls.res_users.browse(cr, uid, uid)
-        self.partner_admin_id = self.user_admin.partner_id.id
+        cls.partner_admin_id = cls.user_admin.partner_id.id
-        self.partner_raoul_id = self.user_raoul.partner_id.id
+        cls.partner_raoul_id = cls.user_raoul.partner_id.id
-        self.partner_bert_id = self.user_bert.partner_id.id
+        cls.partner_bert_id = cls.user_bert.partner_id.id
 
         # Test 'pigs' group to use through the various tests
-        self.group_pigs_id = self.mail_group.create(
+        cls.group_pigs_id = cls.mail_group.create(
             cr, uid,
             {'name': 'Pigs', 'description': 'Fans of Pigs, unite !', 'alias_name': 'group+pigs'},
             {'mail_create_nolog': True}
         )
-        self.group_pigs = self.mail_group.browse(cr, uid, self.group_pigs_id)
+        cls.group_pigs = cls.mail_group.browse(cr, uid, cls.group_pigs_id)
         # Test mail.group: public to provide access to everyone
-        self.group_jobs_id = self.mail_group.create(cr, uid, {'name': 'Jobs', 'public': 'public'})
+        cls.group_jobs_id = cls.mail_group.create(cr, uid, {'name': 'Jobs', 'public': 'public'})
         # Test mail.group: private to restrict access
-        self.group_priv_id = self.mail_group.create(cr, uid, {'name': 'Private', 'public': 'private'})
+        cls.group_priv_id = cls.mail_group.create(cr, uid, {'name': 'Private', 'public': 'private'})
 
-    def tearDown(self):
+    @classmethod
+    def tearDownClass(cls):
         # Remove mocks
-        self.registry('ir.mail_server')._revert_method('build_email')
+        cls.registry('ir.mail_server')._revert_method('build_email')
-        self.registry('ir.mail_server')._revert_method('send_email')
+        cls.registry('ir.mail_server')._revert_method('send_email')
-        super(TestMail, self).tearDown()
+        super(TestMail, cls).tearDownClass()

addons/mail/tests/test_invite.py

@@ -19,7 +19,7 @@
 #
 ##############################################################################
 
-from openerp.addons.mail.tests.common import TestMail
+from .common import TestMail
 
 
 class test_invite(TestMail):

addons/mail/tests/test_mail_features.py

@@ -19,9 +19,9 @@
 #
 ##############################################################################
 
-from openerp.addons.mail.mail_mail import mail_mail
+from ..mail_mail import mail_mail
-from openerp.addons.mail.mail_thread import mail_thread
+from ..mail_thread import mail_thread
-from openerp.addons.mail.tests.common import TestMail
+from .common import TestMail
 from openerp.tools import mute_logger, email_split, html2plaintext
 from openerp.tools.mail import html_sanitize
 

addons/mail/tests/test_mail_gateway.py

@@ -19,7 +19,7 @@
 #
 ##############################################################################
 
-from openerp.addons.mail.tests.common import TestMail
+from .common import TestMail
 from openerp.tools import mute_logger
 import socket
 

addons/mail/tests/test_mail_group.py

@@ -19,7 +19,7 @@
 #
 ##############################################################################
 
-from openerp.addons.mail.tests.common import TestMail
+from .common import TestMail
 from openerp.exceptions import AccessError
 from openerp.osv.orm import except_orm
 from openerp.tools import mute_logger

addons/mail/tests/test_mail_message.py

@@ -19,7 +19,7 @@
 #
 ##############################################################################
 
-from openerp.addons.mail.tests.common import TestMail
+from .common import TestMail
 from openerp.exceptions import AccessError
 from openerp.osv.orm import except_orm
 from openerp.tools import mute_logger

addons/mail/tests/test_message_read.py

@@ -19,7 +19,7 @@
 #
 ##############################################################################
 
-from openerp.addons.mail.tests.common import TestMail
+from .common import TestMail
 
 
 class test_mail_access_rights(TestMail):

addons/portal/tests/test_portal.py

@@ -27,26 +27,26 @@ from openerp.tools.misc import mute_logger
 
 class test_portal(TestMail):
 
-    def setUp(self):
+    @classmethod
-        super(test_portal, self).setUp()
+    def setUpClass(cls):
-        cr, uid = self.cr, self.uid
+        super(test_portal, cls).setUpClass()
+        cr, uid = cls.cr, cls.uid
 
         # Find Portal group
-        group_portal = self.registry('ir.model.data').get_object(cr, uid, 'base', 'group_portal')
+        cls.group_portal_id = cls.env.ref('base.group_portal').id
-        self.group_portal_id = group_portal.id
 
         # Create Chell (portal user)
-        self.user_chell_id = self.res_users.create(cr, uid, {'name': 'Chell Gladys', 'login': 'chell', 'email': 'chell@gladys.portal', 'groups_id': [(6, 0, [self.group_portal_id])]})
+        cls.user_chell_id = cls.res_users.create(cr, uid, {'name': 'Chell Gladys', 'login': 'chell', 'email': 'chell@gladys.portal', 'groups_id': [(6, 0, [cls.group_portal_id])]})
-        self.user_chell = self.res_users.browse(cr, uid, self.user_chell_id)
+        cls.user_chell = cls.res_users.browse(cr, uid, cls.user_chell_id)
-        self.partner_chell_id = self.user_chell.partner_id.id
+        cls.partner_chell_id = cls.user_chell.partner_id.id
 
         # Create a PigsPortal group
-        self.group_port_id = self.mail_group.create(cr, uid,
+        cls.group_port_id = cls.mail_group.create(cr, uid,
-                        {'name': 'PigsPortal', 'public': 'groups', 'group_public_id': self.group_portal_id},
+                        {'name': 'PigsPortal', 'public': 'groups', 'group_public_id': cls.group_portal_id},
                         {'mail_create_nolog': True})
 
         # Set an email address for the user running the tests, used as Sender for outgoing mails
-        self.res_users.write(cr, uid, uid, {'email': 'test@localhost'})
+        cls.res_users.write(cr, uid, uid, {'email': 'test@localhost'})
 
     @mute_logger('openerp.addons.base.ir.ir_model', 'openerp.models')
     def test_00_mail_access_rights(self):

addons/project/tests/test_project_base.py

@@ -24,76 +24,75 @@ from openerp.addons.mail.tests.common import TestMail
 
 class TestProjectBase(TestMail):
 
-    def setUp(self):
+    @classmethod
-        super(TestProjectBase, self).setUp()
+    def setUpClass(cls):
-        cr, uid = self.cr, self.uid
+        super(TestProjectBase, cls).setUpClass()
+        cr, uid = cls.cr, cls.uid
 
         # Usefull models
-        self.project_project = self.registry('project.project')
+        cls.project_project = cls.registry('project.project')
-        self.project_task = self.registry('project.task')
+        cls.project_task = cls.registry('project.task')
-        self.project_task_delegate = self.registry('project.task.delegate')
+        cls.project_task_delegate = cls.registry('project.task.delegate')
 
         # Find Project User group
-        group_project_user_ref = self.registry('ir.model.data').get_object_reference(cr, uid, 'project', 'group_project_user')
+        cls.group_project_user_id = cls.env.ref('project.group_project_user').id or False
-        self.group_project_user_id = group_project_user_ref and group_project_user_ref[1] or False
 
         # Find Project Manager group
-        group_project_manager_ref = self.registry('ir.model.data').get_object_reference(cr, uid, 'project', 'group_project_manager')
+        cls.group_project_manager_id = cls.env.ref('project.group_project_manager').id or False
-        self.group_project_manager_id = group_project_manager_ref and group_project_manager_ref[1] or False
 
         # Test partners to use through the various tests
-        self.project_partner_id = self.res_partner.create(cr, uid, {
+        cls.project_partner_id = cls.res_partner.create(cr, uid, {
             'name': 'Gertrude AgrolaitPartner',
             'email': 'gertrude.partner@agrolait.com',
         })
-        self.email_partner_id = self.res_partner.create(cr, uid, {
+        cls.email_partner_id = cls.res_partner.create(cr, uid, {
             'name': 'Patrick Ratatouille',
             'email': 'patrick.ratatouille@agrolait.com',
         })
 
         # Test users to use through the various tests
-        self.user_projectuser_id = self.res_users.create(cr, uid, {
+        cls.user_projectuser_id = cls.res_users.create(cr, uid, {
             'name': 'Armande ProjectUser',
             'login': 'Armande',
             'alias_name': 'armande',
             'email': 'armande.projectuser@example.com',
-            'groups_id': [(6, 0, [self.group_employee_id, self.group_project_user_id])]
+            'groups_id': [(6, 0, [cls.group_employee_id, cls.group_project_user_id])]
         })
-        self.user_projectmanager_id = self.res_users.create(cr, uid, {
+        cls.user_projectmanager_id = cls.res_users.create(cr, uid, {
             'name': 'Bastien ProjectManager',
             'login': 'bastien',
             'alias_name': 'bastien',
             'email': 'bastien.projectmanager@example.com',
-            'groups_id': [(6, 0, [self.group_employee_id, self.group_project_manager_id])]
+            'groups_id': [(6, 0, [cls.group_employee_id, cls.group_project_manager_id])]
         })
-        self.user_none_id = self.res_users.create(cr, uid, {
+        cls.user_none_id = cls.res_users.create(cr, uid, {
             'name': 'Charlie Avotbonkeur',
             'login': 'charlie',
             'alias_name': 'charlie',
             'email': 'charlie.noone@example.com',
             'groups_id': [(6, 0, [])]
         })
-        self.user_projectuser = self.res_users.browse(cr, uid, self.user_projectuser_id)
+        cls.user_projectuser = cls.res_users.browse(cr, uid, cls.user_projectuser_id)
-        self.user_projectmanager = self.res_users.browse(cr, uid, self.user_projectmanager_id)
+        cls.user_projectmanager = cls.res_users.browse(cr, uid, cls.user_projectmanager_id)
-        self.partner_projectuser_id = self.user_projectuser.partner_id.id
+        cls.partner_projectuser_id = cls.user_projectuser.partner_id.id
-        self.partner_projectmanager_id = self.user_projectmanager.partner_id.id
+        cls.partner_projectmanager_id = cls.user_projectmanager.partner_id.id
 
         # Test 'Pigs' project
-        self.project_pigs_id = self.project_project.create(cr, uid, {
+        cls.project_pigs_id = cls.project_project.create(cr, uid, {
             'name': 'Pigs',
             'privacy_visibility': 'public',
             'alias_name': 'project+pigs',
-            'partner_id': self.partner_raoul_id,
+            'partner_id': cls.partner_raoul_id,
         }, {'mail_create_nolog': True})
 
         # Already-existing tasks in Pigs
-        self.task_1_id = self.project_task.create(cr, uid, {
+        cls.task_1_id = cls.project_task.create(cr, uid, {
             'name': 'Pigs UserTask',
-            'user_id': self.user_projectuser_id,
+            'user_id': cls.user_projectuser_id,
-            'project_id': self.project_pigs_id,
+            'project_id': cls.project_pigs_id,
         }, {'mail_create_nolog': True})
-        self.task_2_id = self.project_task.create(cr, uid, {
+        cls.task_2_id = cls.project_task.create(cr, uid, {
             'name': 'Pigs ManagerTask',
-            'user_id': self.user_projectmanager_id,
+            'user_id': cls.user_projectmanager_id,
-            'project_id': self.project_pigs_id,
+            'project_id': cls.project_pigs_id,
         }, {'mail_create_nolog': True})

addons/project/tests/test_project_flow.py

@@ -19,7 +19,7 @@
 #
 ##############################################################################
 
-from openerp.addons.project.tests.test_project_base import TestProjectBase
+from .test_project_base import TestProjectBase
 from openerp.exceptions import AccessError
 from openerp.tools import mute_logger
 

addons/survey/test/__init__.py

@@ -1,23 +0,0 @@
-# -*- coding: utf-8 -*-
-##############################################################################
-#
-#    OpenERP, Open Source Business Applications
-#    Copyright (c) 2012-TODAY OpenERP S.A. <http://openerp.com>
-#
-#    This program is free software: you can redistribute it and/or modify
-#    it under the terms of the GNU Affero General Public License as
-#    published by the Free Software Foundation, either version 3 of the
-#    License, or (at your option) any later version.
-#
-#    This program is distributed in the hope that it will be useful,
-#    but WITHOUT ANY WARRANTY; without even the implied warranty of
-#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#    GNU Affero General Public License for more details.
-#
-#    You should have received a copy of the GNU Affero General Public License
-#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-#
-##############################################################################
-
-
-from . import test_survey

addons/survey/test/test_survey.py

@@ -1,40 +0,0 @@
-# -*- coding: utf-8 -*-
-##############################################################################
-#
-#    OpenERP, Open Source Business Applications
-#    Copyright (c) 2014-TODAY OpenERP S.A. <http://openerp.com>
-#
-#    This program is free software: you can redistribute it and/or modify
-#    it under the terms of the GNU Affero General Public License as
-#    published by the Free Software Foundation, either version 3 of the
-#    License, or (at your option) any later version.
-#
-#    This program is distributed in the hope that it will be useful,
-#    but WITHOUT ANY WARRANTY; without even the implied warranty of
-#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#    GNU Affero General Public License for more details.
-#
-#    You should have received a copy of the GNU Affero General Public License
-#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-#
-##############################################################################
-
-from openerp.tests import common
-
-
-class test_survey(common.TransactionCase):
-
-    def setUp(self):
-        super(test_survey, self).setUp()
-        cr, uid, context = self.cr, self.uid, {}
-        pass
-
-    def test_00_create_survey_and_questions(self):
-        cr, uid, context = self.cr, self.uid, {}
-        pass
-
-    def test_01_fill_survey(self):
-        pass
-
-    def test_02_answer_survey(self):
-        pass

addons/website_forum/tests/common.py

@@ -15,20 +15,21 @@ KARMA = {
 }
 
 
-class TestForumCommon(common.TransactionCase):
+class TestForumCommon(common.SavepointCase):
 
-    def setUp(self):
+    @classmethod
-        super(TestForumCommon, self).setUp()
+    def setUpClass(cls):
+        super(TestForumCommon, cls).setUpClass()
 
-        Forum = self.env['forum.forum']
+        Forum = cls.env['forum.forum']
-        Post = self.env['forum.post']
+        Post = cls.env['forum.post']
 
         # Test users
-        TestUsersEnv = self.env['res.users'].with_context({'no_reset_password': True})
+        TestUsersEnv = cls.env['res.users'].with_context({'no_reset_password': True})
-        group_employee_id = self.ref('base.group_user')
+        group_employee_id = cls.env.ref('base.group_user').id
-        group_portal_id = self.ref('base.group_portal')
+        group_portal_id = cls.env.ref('base.group_portal').id
-        group_public_id = self.ref('base.group_public')
+        group_public_id = cls.env.ref('base.group_public').id
-        self.user_employee = TestUsersEnv.create({
+        cls.user_employee = TestUsersEnv.create({
             'name': 'Armande Employee',
             'login': 'Armande',
             'alias_name': 'armande',
@@ -36,7 +37,7 @@ class TestForumCommon(common.TransactionCase):
             'karma': 0,
             'groups_id': [(6, 0, [group_employee_id])]
         })
-        self.user_portal = TestUsersEnv.create({
+        cls.user_portal = TestUsersEnv.create({
             'name': 'Beatrice Portal',
             'login': 'Beatrice',
             'alias_name': 'beatrice',
@@ -44,7 +45,7 @@ class TestForumCommon(common.TransactionCase):
             'karma': 0,
             'groups_id': [(6, 0, [group_portal_id])]
         })
-        self.user_public = TestUsersEnv.create({
+        cls.user_public = TestUsersEnv.create({
             'name': 'Cedric Public',
             'login': 'Cedric',
             'alias_name': 'cedric',
@@ -54,7 +55,7 @@ class TestForumCommon(common.TransactionCase):
         })
 
         # Test forum
-        self.forum = Forum.create({
+        cls.forum = Forum.create({
             'name': 'TestForum',
             'karma_ask': KARMA['ask'],
             'karma_answer': KARMA['ans'],
@@ -79,15 +80,15 @@ class TestForumCommon(common.TransactionCase):
             'karma_gen_answer_accept': 9999,
             'karma_gen_answer_accepted': 9999,
         })
-        self.post = Post.create({
+        cls.post = Post.create({
             'name': 'TestQuestion',
             'content': 'I am not a bird.',
-            'forum_id': self.forum.id,
+            'forum_id': cls.forum.id,
-            'tag_ids': [(0, 0, {'name': 'Tag0', 'forum_id': self.forum.id})]
+            'tag_ids': [(0, 0, {'name': 'Tag0', 'forum_id': cls.forum.id})]
         })
-        self.answer = Post.create({
+        cls.answer = Post.create({
             'name': 'TestAnswer',
             'content': 'I am an anteater.',
-            'forum_id': self.forum.id,
+            'forum_id': cls.forum.id,
-            'parent_id': self.post.id,
+            'parent_id': cls.post.id,
         })

addons/website_forum/tests/test_forum.py

@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
-from openerp.addons.website_forum.tests.common import KARMA, TestForumCommon
+from .common import KARMA, TestForumCommon
-from openerp.addons.website_forum.models.forum import KarmaError
+from ..models.forum import KarmaError
 from openerp.exceptions import Warning, AccessError
 from openerp.tools import mute_logger
 

openerp/tests/common.py

@@ -13,6 +13,7 @@ import select
 import subprocess
 import threading
 import time
+import itertools
 import unittest2
 import urllib2
 import xmlrpclib
@@ -171,6 +172,27 @@ class SingleTransactionCase(BaseCase):
         cls.cr.close()
 
 
+savepoint_seq = itertools.count()
+class SavepointCase(SingleTransactionCase):
+    """ Similar to :class:`SingleTransactionCase` in that all test methods
+    are run in a single transaction *but* each test case is run inside a
+    rollbacked savepoint (sub-transaction).
+
+    Useful for test cases containing fast tests but with significant database
+    setup common to all cases (complex in-db test data): :meth:`~.setUpClass`
+    can be used to generate db test data once, then all test cases use the
+    same data without influencing one another but without having to recreate
+    the test data either.
+    """
+    def setUp(self):
+        self._savepoint_id = next(savepoint_seq)
+        self.cr.execute('SAVEPOINT test_%d' % self._savepoint_id)
+    def tearDown(self):
+        self.cr.execute('ROLLBACK TO SAVEPOINT test_%d' % self._savepoint_id)
+        self.env.clear()
+        self.registry.clear_caches()
+
+
 class RedirectHandler(urllib2.HTTPRedirectHandler):
     """
     HTTPRedirectHandler is predicated upon HTTPErrorProcessor being used and