django/tests/regressiontests/null_queries/tests.py

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from django.test import TestCase
from django.core.exceptions import FieldError
from regressiontests.null_queries.models import *
class NullQueriesTests(TestCase):
def test_none_as_null(self):
"""
Regression test for the use of None as a query value.
None is interpreted as an SQL NULL, but only in __exact queries.
Set up some initial polls and choices
"""
p1 = Poll(question='Why?')
p1.save()
c1 = Choice(poll=p1, choice='Because.')
c1.save()
c2 = Choice(poll=p1, choice='Why Not?')
c2.save()
# Exact query with value None returns nothing ("is NULL" in sql,
# but every 'id' field has a value).
self.assertQuerysetEqual(Choice.objects.filter(choice__exact=None), [])
# Excluding the previous result returns everything.
self.assertQuerysetEqual(
Choice.objects.exclude(choice=None).order_by('id'),
[
'<Choice: Choice: Because. in poll Q: Why? >',
'<Choice: Choice: Why Not? in poll Q: Why? >'
]
)
# Valid query, but fails because foo isn't a keyword
self.assertRaises(FieldError, Choice.objects.filter, foo__exact=None)
# Can't use None on anything other than __exact
self.assertRaises(ValueError, Choice.objects.filter, id__gt=None)
# Can't use None on anything other than __exact
self.assertRaises(ValueError, Choice.objects.filter, foo__gt=None)
# Related managers use __exact=None implicitly if the object hasn't been saved.
p2 = Poll(question="How?")
self.assertEqual(repr(p2.choice_set.all()), '[]')
def test_reverse_relations(self):
"""
Querying across reverse relations and then another relation should
insert outer joins correctly so as not to exclude results.
"""
obj = OuterA.objects.create()
self.assertQuerysetEqual(
OuterA.objects.filter(inner__second=None),
['<OuterA: OuterA object>']
)
self.assertQuerysetEqual(
OuterA.objects.filter(inner__second__data=None),
['<OuterA: OuterA object>']
)
inner_obj = Inner.objects.create(first=obj)
self.assertQuerysetEqual(
Inner.objects.filter(first__inner__second=None),
['<Inner: Inner object>']
)
# Ticket #13815: check if <reverse>_isnull=False does not produce
# faulty empty lists
objB = OuterB.objects.create(data="reverse")
self.assertQuerysetEqual(
OuterB.objects.filter(inner__isnull=False),
[]
)
Inner.objects.create(first=obj)
self.assertQuerysetEqual(
OuterB.objects.exclude(inner__isnull=False),
['<OuterB: OuterB object>']
)