[FIX] l10n_ch: TestOnchangePostal, TestSwissQR relied on demo data

The partner created in TestOnchangePostal and the product created in
TestSwissQR were taken from demo data, which might not be installed
in the test environment, so the create_invoice() method could
raise a traceback.

Part-of: odoo/odoo#77295

addons/l10n_ch/tests/test_onchange_l10n_ch_postal.py

@@ -18,7 +18,15 @@ class TestOnchangePostal(TransactionCase):
     def setUpClass(cls):
         super().setUpClass()
         cls.env = cls.env(context=dict(cls.env.context, tracking_disable=True))
-        cls.partner = cls.env.ref('base.res_partner_12')
+
+        cls.partner = cls.env['res.partner'].create({
+            'name': 'Swiss Company',
+            'street': 'Route de Berne 41',
+            'zip': '1000',
+            'city': 'Lausanne',
+            'is_company': 1,
+            'country_id': cls.env.ref('base.ch').id,
+        })
         cls.ch_bank = cls.env['res.bank'].create({
             'name': 'Alternative Bank Schweiz AG',
             'bic': 'ALSWCH21XXX',

addons/l10n_ch/tests/test_swissqr.py

@@ -41,6 +41,9 @@ class TestSwissQR(AccountTestInvoicingCommon):
                 "country_id": self.env.ref('base.ch').id,
             }
         )
+        self.product = self.env['product.product'].create({
+            'name': 'Customizable Desk',
+        })
         self.invoice1 = self.create_invoice('base.CHF')
         sale_journal = self.env['account.journal'].search([("type", "=", "sale")])
         sale_journal.invoice_reference_model = "ch"
@@ -48,7 +51,6 @@ class TestSwissQR(AccountTestInvoicingCommon):
     def create_invoice(self, currency_to_use='base.CHF'):
         """ Generates a test invoice """
 
-        product = self.env.ref("product.product_product_4")
         acc_type = self.env.ref('account.data_account_type_current_assets')
         account = self.env['account.account'].search(
             [('user_type_id', '=', acc_type.id)], limit=1
@@ -66,8 +68,8 @@ class TestSwissQR(AccountTestInvoicingCommon):
                             0,
                             0,
                             {
-                                'name': product.name,
-                                'product_id': product.id,
+                                'name': self.product.name,
+                                'product_id': self.product.id,
                                 'account_id': account.id,
                                 'quantity': 1,
                                 'price_unit': 42.0,