[FIX] hr_holidays: ensure consistency with cap accrued time

Steps to reproduce:
-------------------
- create a time off accrual plan with:
    - cap accrued time equals to `True`
    - maximum leave equals to `0 days`
- create an allocation with this accrual plan
- run the scheduled action "Accrual Time Off: Updates the number of time off"
    (make sure you have the right "lastcall" and "nextcall")

Issue:
------
The number of days of the allocation is set to zero.
This scenario makes no sense from a business point of view.
In effect, we are blocking the accumulation of allocations at zero.
The result is that there will never be any days allocated to these allocations.

Solution:
---------
Add a constraint to force a maximum leave number
when cap accrued time is set.

opw-3847408

closes odoo/odoo#160626

Signed-off-by: Bertrand Dossogne (bedo) <bedo@odoo.com>

addons/hr_holidays/i18n/hr_holidays.pot

@@ -4441,6 +4441,14 @@ msgid ""
 " manager"
 msgstr ""
 
+#. module: hr_holidays
+#. odoo-python
+#: code:addons/hr_holidays/models/hr_leave_accrual_plan_level.py:0
+#, python-format
+msgid ""
+"You cannot have a cap on accrued time without setting a maximum amount."
+msgstr ""
+
 #. module: hr_holidays
 #. odoo-python
 #: code:addons/hr_holidays/models/hr_leave_allocation.py:0

addons/hr_holidays/models/hr_leave_accrual_plan_level.py

@@ -4,6 +4,7 @@
 from dateutil.relativedelta import relativedelta
 
 from odoo import _, api, fields, models
+from odoo.exceptions import UserError
 
 
 DAYS = ['sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat']
@@ -134,6 +135,12 @@ class AccrualPlanLevel(models.Model):
         ('added_value_greater_than_zero', 'CHECK(added_value > 0)', 'You must give a rate greater than 0 in accrual plan levels.')
     ]
 
+    @api.constrains('maximum_leave')
+    def _check_maximum_leave(self):
+        for level in self:
+            if level.cap_accrued_time and level.maximum_leave < 1:
+                raise UserError(_("You cannot have a cap on accrued time without setting a maximum amount."))
+
     @api.depends('start_count', 'start_type')
     def _compute_sequence(self):
         # Not 100% accurate because of odd months/years, but good enough

addons/hr_holidays/tests/test_accrual_allocations.py

@@ -5,6 +5,7 @@ from freezegun import freeze_time
 from dateutil.relativedelta import relativedelta
 
 from odoo import Command
+from odoo.exceptions import UserError
 from odoo.tests import tagged
 
 from odoo.addons.hr_holidays.tests.common import TestHrHolidaysCommon
@@ -41,6 +42,29 @@ class TestAccrualAllocations(TestHrHolidaysCommon):
                        WHERE id = %s
                        """ % (date, allocation_id))
 
+    def test_consistency_between_cap_accrued_time_and_maximum_leave(self):
+        accrual_plan = self.env['hr.leave.accrual.plan'].with_context(tracking_disable=True).create({
+            'name': 'Accrual Plan For Test',
+            'level_ids': [(0, 0, {
+                'start_count': 1,
+                'start_type': 'day',
+                'added_value': 1,
+                'added_value_type': 'day',
+                'frequency': 'hourly',
+                'cap_accrued_time': True,
+                'maximum_leave': 10000
+            })],
+        })
+        level = accrual_plan.level_ids
+        level.maximum_leave = 10
+        self.assertEqual(accrual_plan.level_ids.maximum_leave, 10)
+
+        with self.assertRaises(UserError):
+            level.maximum_leave = 0
+
+        level.cap_accrued_time = False
+        self.assertEqual(accrual_plan.level_ids.maximum_leave, 0)
+
     def test_frequency_hourly_calendar(self):
         with freeze_time("2017-12-5"):
             accrual_plan = self.env['hr.leave.accrual.plan'].with_context(tracking_disable=True).create({