[ADD] test_timer: Add test module for the timer mixin

Purpose
=======

As testing the mixin requires to create a new model,
we prefered to create another module.

TaskID: 2149450

addons/test_timer/models/timer_test.py

@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+# Part of Odoo. See LICENSE file for full copyright and licensing details.
+
+from odoo import fields, models
+
+
+class TimerTest(models.Model):
+    """ A very simple model only inheriting from timer.mixin to test
+    timer features """
+    _description = 'Timer Model'
+    _name = 'timer.test'
+    _inherit = ['timer.mixin']
+
+    name = fields.Char(required=1)
+
+
+class OverrideInterruptionTimerTest(models.Model):
+    """ A very simple model inheriting from timer.mixin and
+    overriding _action_interrupt_user_timers() """
+    _description = 'Interruption Timer Model'
+    _name = 'interruption.timer.test'
+    _inherit = ['timer.mixin']
+
+    def _action_interrupt_user_timers(self):
+        self.action_timer_stop()