from __future__ import absolute_import, unicode_literals

from django.utils.six import StringIO

from django.contrib.auth.models import Permission
from django.contrib.contenttypes.models import ContentType
from django.core import management
from django.db.models.loading import cache
from django.test import TestCase
from django.test.utils import override_settings


class SwappableModelTests(TestCase):
    def setUp(self):
        # This test modifies the installed apps, so we need to make sure
        # we're not dealing with a cached app list.
        cache._get_models_cache.clear()

    def tearDown(self):
        # By fiddling with swappable models, we alter the installed models
        # cache, so flush it to make sure there are no side effects.
        cache._get_models_cache.clear()

    @override_settings(TEST_ARTICLE_MODEL='swappable_models.AlternateArticle')
    def test_generated_data(self):
        "Permissions and content types are not created for a swapped model"

        # Delete all permissions and content_types
        Permission.objects.all().delete()
        ContentType.objects.all().delete()

        # Re-run syncdb. This will re-build the permissions and content types.
        new_io = StringIO()
        management.call_command('syncdb', load_initial_data=False, interactive=False, stdout=new_io)

        # Check that content types and permissions exist for the swapped model,
        # but not for the swappable model.
        apps_models = [(p.content_type.app_label, p.content_type.model)
                       for p in Permission.objects.all()]
        self.assertIn(('swappable_models', 'alternatearticle'), apps_models)
        self.assertNotIn(('swappable_models', 'article'), apps_models)

        apps_models = [(ct.app_label, ct.model)
                       for ct in ContentType.objects.all()]
        self.assertIn(('swappable_models', 'alternatearticle'), apps_models)
        self.assertNotIn(('swappable_models', 'article'), apps_models)