from django.test import TestCase
from .models import Article, Author, Comment, Forum, Post, SystemInfo
class NullFkOrderingTests(TestCase):
def test_ordering_across_null_fk(self):
"""
Regression test for #7512ordering across nullable Foreign Keys shouldn't exclude results"""author_1 = Author.objects.create(name="Tom Jones")
author_2 = Author.objects.create(name="Bob Smith")
Article.objects.create(title="No author on this article")
Article.objects.create(
author=author_1, title="This article written by Tom Jones"
)Article.objects.create(
author=author_2, title="This article written by Bob Smith"
)# We can't compare results directly (since different databases sort NULLs to
# different ends of the ordering), but we can check that all results are
# returned.
self.assertEqual(len(list(Article.objects.all())), 3)
s = SystemInfo.objects.create(system_name="System Info")
f = Forum.objects.create(system_info=s, forum_name="First forum")
p = Post.objects.create(forum=f, title="First Post")
Comment.objects.create(post=p, comment_text="My first comment")
Comment.objects.create(comment_text="My second comment")
s2 = SystemInfo.objects.create(system_name="More System Info")
f2 = Forum.objects.create(system_info=s2, forum_name="Second forum")
p2 = Post.objects.create(forum=f2, title="Second Post")
Comment.objects.create(comment_text="Another first comment")
Comment.objects.create(post=p2, comment_text="Another second comment")
# We have to test this carefully. Some databases sort NULL values before
# everything else, some sort them afterward. So we extract the ordered list
# and check the length. Before the fix, this list was too short (some values
# were omitted).
self.assertEqual(len(list(Comment.objects.all())), 4)