from __future__ import absolute_import from django.test import TestCase from django.core.exceptions import FieldError from .models import Poll, Choice, OuterA, Inner, OuterB 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'), [ '', '' ] ) # 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), [''] ) self.assertQuerysetEqual( OuterA.objects.filter(inner__second__data=None), [''] ) inner_obj = Inner.objects.create(first=obj) self.assertQuerysetEqual( Inner.objects.filter(first__inner__second=None), [''] ) # Ticket #13815: check if _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), [''] )