from __future__ import absolute_import, unicode_literals

import os

from django.core.management import call_command
from django.test import TestCase, TransactionTestCase
from django.test.utils import override_system_checks, extend_sys_path
from django.utils._os import upath

from .models import (ConcreteModel, ConcreteModelSubclass,
    ConcreteModelSubclassProxy)


class ProxyModelInheritanceTests(TransactionTestCase):
    """
    Proxy model inheritance across apps can result in migrate not creating the table
    for the proxied model (as described in #12286).  This test creates two dummy
    apps and calls migrate, then verifies that the table has been created.
    """
    available_apps = []

    # `auth` app is imported, but not installed in this test, so we need to
    # exclude checks registered by this app.
    @override_system_checks([])
    def test_table_exists(self):
        with extend_sys_path(os.path.dirname(os.path.abspath(upath(__file__)))):
            with self.modify_settings(INSTALLED_APPS={'append': ['app1', 'app2']}):
                call_command('migrate', verbosity=0)
                from app1.models import ProxyModel
                from app2.models import NiceModel
                self.assertEqual(NiceModel.objects.all().count(), 0)
                self.assertEqual(ProxyModel.objects.all().count(), 0)


class MultiTableInheritanceProxyTest(TestCase):

    def test_model_subclass_proxy(self):
        """
        Deleting an instance of a model proxying a multi-table inherited
        subclass should cascade delete down the whole inheritance chain (see
        #18083).
        """
        instance = ConcreteModelSubclassProxy.objects.create()
        instance.delete()
        self.assertEqual(0, ConcreteModelSubclassProxy.objects.count())
        self.assertEqual(0, ConcreteModelSubclass.objects.count())
        self.assertEqual(0, ConcreteModel.objects.count())