[IMP] energy_selfconsumption: added unit testing for quantity and price unit generation

For some reason when executing unit testing and validating this part of the code it raises because it can't found any record in inscriptions_ids if called from the selfconsumption model instead of the project.

energy_selfconsumption/tests/test_contract_generation_wizard.py

@@ -80,3 +80,16 @@ class TestContractGenerationWizard(TransactionCase):
     def test_generation_contracts(self):
         res = self.contract_generation_wizard.generate_contracts_button()
         self.assertEqual(res, True)
+
+        related_contract = self.env["contract.contract"].search(
+            [("project_id", "=", self.selfconsumption.project_id.id)]
+        )
+        contract_line = related_contract[0].contract_line_ids[0]
+        days_timedelta = (
+            contract_line.next_period_date_end - contract_line.next_period_date_start
+        )
+        expected_quantity = 100 * 1 * (days_timedelta.days + 1)
+        related_contract[0].recurring_create_invoice()
+        invoice = related_contract._get_related_invoices()
+        self.assertEqual(invoice.invoice_line_ids[0].quantity, expected_quantity)
+        self.assertEqual(invoice.invoice_line_ids[0].price_unit, 0.1)