from django.db.models.deletion import Collector, ProtectedError


def delete_child_instances(instance):
    try:
        collector = Collector(using='default')
        collector.collect(objs=[instance], collect_related=True)
    except ProtectedError as error:
        protected_objects = error.protected_objects
        for obj in protected_objects:
            delete_child_instances(obj)
            obj.deleted = True
            obj.save()


    def test_cascading_deletes(self):
        contact_type = mommy.make(ContactType)
        contact_1 = mommy.make(Contact, contact_type=contact_type)
        contact_2 = mommy.make(Contact, contact_type=contact_type)
        url = reverse("api:common:contact_types_list")
        url = url + "{}/".format(contact_type)
        response = self.client.delete(url)
        # wait for  15 seconds for the cache
        time.sleep(20)
        self.assertEquals(204, response.status_code)
        self.assertTrue(contact_type.deleted)
        self.assertTrue(contact_1.deleted)
        self.assertTrue(contact_2.deleted)