[13.0][FIX] contract: Recompute recurring next date

After invoice creation, the recurring next date has to be recomputed
in order to get good values

contract/models/contract.py

@@ -465,7 +465,9 @@ class ContractContract(models.Model):
 
     def _recurring_create_invoice(self, date_ref=False):
         invoices_values = self._prepare_recurring_invoices_values(date_ref)
-        return self.env["account.move"].create(invoices_values)
+        moves = self.env["account.move"].create(invoices_values)
+        self._compute_recurring_next_date()
+        return moves
 
     @api.model
     def cron_recurring_create_invoice(self, date_ref=None):

contract/tests/test_contract.py

@@ -123,6 +123,41 @@ class TestContractBase(common.SavepointCase):
             {"name": "terminate_reason"}
         )
 
+        cls.contract3 = cls.env["contract.contract"].create(
+            {
+                "name": "Test Contract 3",
+                "partner_id": cls.partner.id,
+                "pricelist_id": cls.partner.property_product_pricelist.id,
+                "line_recurrence": False,
+                "contract_type": "sale",
+                "recurring_interval": 1,
+                "recurring_rule_type": "monthly",
+                "date_start": "2018-02-15",
+                "contract_line_ids": [
+                    (
+                        0,
+                        0,
+                        {
+                            "product_id": False,
+                            "name": "Services from #START# to #END#",
+                            "quantity": 1,
+                            "price_unit": 100,
+                        },
+                    ),
+                    (
+                        0,
+                        0,
+                        {
+                            "product_id": False,
+                            "name": "Line",
+                            "quantity": 1,
+                            "price_unit": 120,
+                        },
+                    ),
+                ],
+            }
+        )
+
 
 class TestContract(TestContractBase):
     def _add_template_line(self, overrides=None):
@@ -169,6 +204,10 @@ class TestContract(TestContractBase):
         self.assertAlmostEqual(self.inv_line.price_subtotal, 50.0)
         self.assertEqual(self.contract.user_id, self.invoice_monthly.user_id)
 
+    def test_contract_level_recurrence(self):
+        self.contract3.recurring_create_invoice()
+        self.contract3.flush()
+
     def test_contract_daily(self):
         recurring_next_date = to_date("2018-02-23")
         last_date_invoiced = to_date("2018-02-22")