[FIX] account_netting: Fallback to load CoA

Since odoo/odoo@d0342c8, the default existing company is not getting a
CoA automatically, provoking than the current tests fail with the error:

odoo.exceptions.UserError: No journal could be found in company My Company (San Francisco) for any of those types: sale

Thus, we put tests post-install for being sure localization modules are
installed, the same as AccountTestInvoicingCommon does, but we don't
inherit from it, as it creates an overhead creating 2 new companies and
loading their CoA and some more stuff, while we don't need all of that.

Besides, if you don't have `l10n_generic_coa` installed, you can't use
another CoA (like `l10n_es`) easily, so we put little code to select the
first available CoA.

account_netting/tests/test_account_netting.py

@@ -16,6 +16,15 @@ class TestAccountNetting(common.TransactionCase):
     def setUpClass(cls):
         super().setUpClass()
         cls.env = cls.env(context=dict(cls.env.context, tracking_disable=True))
+        if not cls.env.company.chart_template_id:
+            # Load a CoA if there's none in current company
+            coa = cls.env.ref("l10n_generic_coa.configurable_chart_template", False)
+            if not coa:
+                # Load the first available CoA
+                coa = cls.env["account.chart.template"].search(
+                    [("visible", "=", True)], limit=1
+                )
+            coa.try_loading(company=cls.env.company, install_demo=False)
         res_users_account_manager = cls.env.ref("account.group_account_manager")
         partner_manager = cls.env.ref("base.group_partner_manager")
         cls.env.user.write(