python/lib/django_1_4/tests/regressiontests/null_queries/tests.py

   1 from __future__ import absolute_import
   2
   3 from django.test import TestCase
   4 from django.core.exceptions import FieldError
   5
   6 from .models import Poll, Choice, OuterA, Inner, OuterB
   7
   8
   9 class NullQueriesTests(TestCase):
  10
  11     def test_none_as_null(self):
  12         """
  13         Regression test for the use of None as a query value.
  14
  15         None is interpreted as an SQL NULL, but only in __exact queries.
  16         Set up some initial polls and choices
  17         """
  18         p1 = Poll(question='Why?')
  19         p1.save()
  20         c1 = Choice(poll=p1, choice='Because.')
  21         c1.save()
  22         c2 = Choice(poll=p1, choice='Why Not?')
  23         c2.save()
  24
  25         # Exact query with value None returns nothing ("is NULL" in sql,
  26         # but every 'id' field has a value).
  27         self.assertQuerysetEqual(Choice.objects.filter(choice__exact=None), [])
  28
  29         # Excluding the previous result returns everything.
  30         self.assertQuerysetEqual(
  31                 Choice.objects.exclude(choice=None).order_by('id'),
  32                 [
  33                     '<Choice: Choice: Because. in poll Q: Why? >',
  34                     '<Choice: Choice: Why Not? in poll Q: Why? >'
  35                 ]
  36         )
  37
  38         # Valid query, but fails because foo isn't a keyword
  39         self.assertRaises(FieldError, Choice.objects.filter, foo__exact=None)
  40
  41         # Can't use None on anything other than __exact
  42         self.assertRaises(ValueError, Choice.objects.filter, id__gt=None)
  43
  44         # Can't use None on anything other than __exact
  45         self.assertRaises(ValueError, Choice.objects.filter, foo__gt=None)
  46
  47         # Related managers use __exact=None implicitly if the object hasn't been saved.
  48         p2 = Poll(question="How?")
  49         self.assertEqual(repr(p2.choice_set.all()), '[]')
  50
  51     def test_reverse_relations(self):
  52         """
  53         Querying across reverse relations and then another relation should
  54         insert outer joins correctly so as not to exclude results.
  55         """
  56         obj = OuterA.objects.create()
  57         self.assertQuerysetEqual(
  58             OuterA.objects.filter(inner__second=None),
  59             ['<OuterA: OuterA object>']
  60         )
  61         self.assertQuerysetEqual(
  62             OuterA.objects.filter(inner__second__data=None),
  63             ['<OuterA: OuterA object>']
  64         )
  65
  66         inner_obj = Inner.objects.create(first=obj)
  67         self.assertQuerysetEqual(
  68             Inner.objects.filter(first__inner__second=None),
  69             ['<Inner: Inner object>']
  70         )
  71
  72         # Ticket #13815: check if <reverse>_isnull=False does not produce
  73         # faulty empty lists
  74         objB = OuterB.objects.create(data="reverse")
  75         self.assertQuerysetEqual(
  76             OuterB.objects.filter(inner__isnull=False),
  77             []
  78         )
  79         Inner.objects.create(first=obj)
  80         self.assertQuerysetEqual(
  81             OuterB.objects.exclude(inner__isnull=False),
  82             ['<OuterB: OuterB object>']
  83         )