from django.core.exceptions import FieldError from django.test import TestCase from .models import Choice, Inner, OuterA, OuterB, Poll 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 and __iexact 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.assertSequenceEqual(Choice.objects.filter(choice__exact=None), []) # The same behavior for iexact query. self.assertSequenceEqual(Choice.objects.filter(choice__iexact=None), []) # Excluding the previous result returns everything. self.assertSequenceEqual(Choice.objects.exclude(choice=None).order_by('id'), [c1, c2]) # Valid query, but fails because foo isn't a keyword msg = "Cannot resolve keyword 'foo' into field. Choices are: choice, id, poll, poll_id" with self.assertRaisesMessage(FieldError, msg): Choice.objects.filter(foo__exact=None) # Can't use None on anything other than __exact and __iexact with self.assertRaisesMessage(ValueError, 'Cannot use None as a query value'): Choice.objects.filter(id__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.assertSequenceEqual(OuterA.objects.filter(inner__third=None), [obj]) self.assertSequenceEqual(OuterA.objects.filter(inner__third__data=None), [obj]) inner = Inner.objects.create(first=obj) self.assertSequenceEqual(Inner.objects.filter(first__inner__third=None), [inner]) # Ticket #13815: check if _isnull=False does not produce # faulty empty lists outerb = OuterB.objects.create(data='reverse') self.assertSequenceEqual(OuterB.objects.filter(inner__isnull=False), []) Inner.objects.create(first=obj) self.assertSequenceEqual(OuterB.objects.exclude(inner__isnull=False), [outerb])