[IMP] membership: Remove dependency to AccountTestCommon

l10n runbot builds are all failing when running at least one test depending of AccountTestCommon because it:
- doesn't create a sandboxed testing environnement to manage the multi-currency, multi-company, the default company's currency, the exchange rates...
- doesn't setup a testing user then all tests are done using the superuser.
- doesn't provide a fully setup chart of accounts: exchange difference journal is not set, accounts have bad types, etc...
- is run sometimes at-install.

--task: 2296213

addons/membership/tests/common.py

@@ -3,19 +3,17 @@
 import datetime
 from dateutil.relativedelta import relativedelta
 
-from odoo.addons.account.tests.common import AccountTestCommon
+from odoo.addons.account.tests.common import AccountTestInvoicingCommon
 
 
-class TestMembershipCommon(AccountTestCommon):
+class TestMembershipCommon(AccountTestInvoicingCommon):
 
-    def setUp(self):
-        super(TestMembershipCommon, self).setUp()
-
-        # Usefull models
-        Partner = self.env['res.partner']
+    @classmethod
+    def setUpClass(cls, chart_template_ref=None):
+        super().setUpClass(chart_template_ref=chart_template_ref)
 
         # Test memberships
-        self.membership_1 = self.env['product.product'].create({
+        cls.membership_1 = cls.env['product.product'].create({
             'membership': True,
             'membership_date_from': datetime.date.today() + relativedelta(days=-2),
             'membership_date_to': datetime.date.today() + relativedelta(months=1),
@@ -25,10 +23,10 @@ class TestMembershipCommon(AccountTestCommon):
         })
 
         # Test people
-        self.partner_1 = Partner.create({
+        cls.partner_1 = cls.env['res.partner'].create({
             'name': 'Ignasse Reblochon',
         })
-        self.partner_2 = Partner.create({
+        cls.partner_2 = cls.env['res.partner'].create({
             'name': 'Martine Poulichette',
             'free_member': True,
         })