from __future__ import with_statement, absolute_import from operator import attrgetter from django.contrib.contenttypes.models import ContentType from django.contrib.sessions.backends.db import SessionStore from django.db.models import Count from django.db.models.loading import cache from django.test import TestCase from .models import (ResolveThis, Item, RelatedItem, Child, Leaf, Proxy, SimpleItem, Feature) class DeferRegressionTest(TestCase): def test_basic(self): # Deferred fields should really be deferred and not accidentally use # the field's default value just because they aren't passed to __init__ Item.objects.create(name="first", value=42) obj = Item.objects.only("name", "other_value").get(name="first") # Accessing "name" doesn't trigger a new database query. Accessing # "value" or "text" should. with self.assertNumQueries(0): self.assertEqual(obj.name, "first") self.assertEqual(obj.other_value, 0) with self.assertNumQueries(1): self.assertEqual(obj.value, 42) with self.assertNumQueries(1): self.assertEqual(obj.text, "xyzzy") with self.assertNumQueries(0): self.assertEqual(obj.text, "xyzzy") # Regression test for #10695. Make sure different instances don't # inadvertently share data in the deferred descriptor objects. i = Item.objects.create(name="no I'm first", value=37) items = Item.objects.only("value").order_by("-value") self.assertEqual(items[0].name, "first") self.assertEqual(items[1].name, "no I'm first") RelatedItem.objects.create(item=i) r = RelatedItem.objects.defer("item").get() self.assertEqual(r.item_id, i.id) self.assertEqual(r.item, i) # Some further checks for select_related() and inherited model # behaviour (regression for #10710). c1 = Child.objects.create(name="c1", value=42) c2 = Child.objects.create(name="c2", value=37) Leaf.objects.create(name="l1", child=c1, second_child=c2) obj = Leaf.objects.only("name", "child").select_related()[0] self.assertEqual(obj.child.name, "c1") self.assertQuerysetEqual( Leaf.objects.select_related().only("child__name", "second_child__name"), [ "l1", ], attrgetter("name") ) # Models instances with deferred fields should still return the same # content types as their non-deferred versions (bug #10738). ctype = ContentType.objects.get_for_model c1 = ctype(Item.objects.all()[0]) c2 = ctype(Item.objects.defer("name")[0]) c3 = ctype(Item.objects.only("name")[0]) self.assertTrue(c1 is c2 is c3) # Regression for #10733 - only() can be used on a model with two # foreign keys. results = Leaf.objects.only("name", "child", "second_child").select_related() self.assertEqual(results[0].child.name, "c1") self.assertEqual(results[0].second_child.name, "c2") results = Leaf.objects.only("name", "child", "second_child", "child__name", "second_child__name").select_related() self.assertEqual(results[0].child.name, "c1") self.assertEqual(results[0].second_child.name, "c2") # Test for #12163 - Pickling error saving session with unsaved model # instances. SESSION_KEY = '2b1189a188b44ad18c35e1baac6ceead' item = Item() item._deferred = False s = SessionStore(SESSION_KEY) s.clear() s["item"] = item s.save() s = SessionStore(SESSION_KEY) s.modified = True s.save() i2 = s["item"] self.assertFalse(i2._deferred) # Regression for #11936 - loading.get_models should not return deferred # models by default. klasses = sorted( cache.get_models(cache.get_app("defer_regress")), key=lambda klass: klass.__name__ ) self.assertEqual( klasses, [ Child, Feature, Item, Leaf, Proxy, RelatedItem, ResolveThis, SimpleItem, ] ) klasses = sorted( map( attrgetter("__name__"), cache.get_models( cache.get_app("defer_regress"), include_deferred=True ), ) ) self.assertEqual( klasses, [ "Child", "Child_Deferred_value", "Feature", "Item", "Item_Deferred_name", "Item_Deferred_name_other_value_text", "Item_Deferred_name_other_value_value", "Item_Deferred_other_value_text_value", "Item_Deferred_text_value", "Leaf", "Leaf_Deferred_child_id_second_child_id_value", "Leaf_Deferred_name_value", "Leaf_Deferred_second_child_value", "Leaf_Deferred_value", "Proxy", "RelatedItem", "RelatedItem_Deferred_", "RelatedItem_Deferred_item_id", "ResolveThis", "SimpleItem", ] ) # Regression for #16409 - make sure defer() and only() work with annotate() self.assertIsInstance(list(SimpleItem.objects.annotate(Count('feature')).defer('name')), list) self.assertIsInstance(list(SimpleItem.objects.annotate(Count('feature')).only('name')), list) def test_only_and_defer_usage_on_proxy_models(self): # Regression for #15790 - only() broken for proxy models proxy = Proxy.objects.create(name="proxy", value=42) msg = 'QuerySet.only() return bogus results with proxy models' dp = Proxy.objects.only('other_value').get(pk=proxy.pk) self.assertEqual(dp.name, proxy.name, msg=msg) self.assertEqual(dp.value, proxy.value, msg=msg) # also test things with .defer() msg = 'QuerySet.defer() return bogus results with proxy models' dp = Proxy.objects.defer('name', 'text', 'value').get(pk=proxy.pk) self.assertEqual(dp.name, proxy.name, msg=msg) self.assertEqual(dp.value, proxy.value, msg=msg) def test_resolve_columns(self): rt = ResolveThis.objects.create(num=5.0, name='Foobar') qs = ResolveThis.objects.defer('num') self.assertEqual(1, qs.count()) self.assertEqual('Foobar', qs[0].name)