[REF] contract: refactor _update_recurring_next_date

Reuse the logic that is now fully located in _get_recurring_next_date.

contract/models/contract_line.py

@@ -675,23 +675,18 @@ class ContractLine(models.Model):
     @api.multi
     def _update_recurring_next_date(self):
         for rec in self:
-            old_date = rec.recurring_next_date
-            new_date = old_date + self.get_relative_delta(
-                rec.recurring_rule_type, rec.recurring_interval
+            last_date_invoiced = rec.next_period_date_end
+            recurring_next_date = rec._get_recurring_next_date(
+                last_date_invoiced + relativedelta(days=1),
+                rec.recurring_invoicing_type,
+                rec.recurring_rule_type,
+                rec.recurring_interval,
+                max_date_end=rec.date_end,
             )
-            if rec.recurring_rule_type == 'monthlylastday':
-                last_date_invoiced = old_date
-            elif rec.recurring_invoicing_type == 'post-paid':
-                last_date_invoiced = old_date - relativedelta(days=1)
-            elif rec.recurring_invoicing_type == 'pre-paid':
-                last_date_invoiced = new_date - relativedelta(days=1)
-
-            if rec.date_end and last_date_invoiced >= rec.date_end:
-                rec.last_date_invoiced = rec.date_end
-                rec.recurring_next_date = False
-            else:
-                rec.last_date_invoiced = last_date_invoiced
-                rec.recurring_next_date = new_date
+            rec.write({
+                "recurring_next_date": recurring_next_date,
+                "last_date_invoiced": last_date_invoiced,
+            })
 
     @api.multi
     def _init_last_date_invoiced(self):

contract/tests/test_contract.py

@@ -247,7 +247,7 @@ class TestContract(TestContractBase):
         self.assertEqual(self.acct_line.last_date_invoiced, last_date_invoiced)
 
     def test_contract_monthly_lastday(self):
-        recurring_next_date = to_date('2018-03-31')
+        recurring_next_date = to_date('2018-02-28')
         last_date_invoiced = to_date('2018-02-22')
         self.acct_line.recurring_next_date = '2018-02-22'
         self.acct_line.recurring_invoicing_type = 'post-paid'
@@ -279,7 +279,7 @@ class TestContract(TestContractBase):
         )
         self.contract.recurring_create_invoice()
         self.assertEqual(
-            self.acct_line.recurring_next_date, to_date('2018-04-01')
+            self.acct_line.recurring_next_date, to_date('2018-3-16')
         )
         self.assertEqual(
             self.acct_line.last_date_invoiced, to_date('2018-02-28')