from django.test import TestCase from regressiontests.null_fk.models import * class NullFkTests(TestCase): def test_null_fk(self): d = SystemDetails.objects.create(details='First details') s = SystemInfo.objects.create(system_name='First forum', system_details=d) f = Forum.objects.create(system_info=s, forum_name='First forum') p = Post.objects.create(forum=f, title='First Post') c1 = Comment.objects.create(post=p, comment_text='My first comment') c2 = Comment.objects.create(comment_text='My second comment') # Starting from comment, make sure that a .select_related(...) with a specified # set of fields will properly LEFT JOIN multiple levels of NULLs (and the things # that come after the NULLs, or else data that should exist won't). Regression # test for #7369. c = Comment.objects.select_related().get(id=c1.id) self.assertEqual(c.post, p) self.assertEqual(Comment.objects.select_related().get(id=c2.id).post, None) self.assertQuerysetEqual( Comment.objects.select_related('post__forum__system_info').all(), [ (c1.id, u'My first comment', ''), (c2.id, u'My second comment', 'None') ], transform = lambda c: (c.id, c.comment_text, repr(c.post)) ) # Regression test for #7530, #7716. self.assertTrue(Comment.objects.select_related('post').filter(post__isnull=True)[0].post is None) self.assertQuerysetEqual( Comment.objects.select_related('post__forum__system_info__system_details'), [ (c1.id, u'My first comment', ''), (c2.id, u'My second comment', 'None') ], transform = lambda c: (c.id, c.comment_text, repr(c.post)) )