diff --git a/tests/modeltests/defer/models.py b/tests/modeltests/defer/models.py index ac3c876a57..4fddd39d26 100644 --- a/tests/modeltests/defer/models.py +++ b/tests/modeltests/defer/models.py @@ -3,7 +3,7 @@ Tests for defer() and only(). """ from django.db import models -from django.db.models.query_utils import DeferredAttribute + class Secondary(models.Model): first = models.CharField(max_length=50) @@ -22,165 +22,3 @@ class Child(Primary): class BigChild(Primary): other = models.CharField(max_length=50) - -def count_delayed_fields(obj, debug=False): - """ - Returns the number of delayed attributes on the given model instance. - """ - count = 0 - for field in obj._meta.fields: - if isinstance(obj.__class__.__dict__.get(field.attname), - DeferredAttribute): - if debug: - print field.name, field.attname - count += 1 - return count - - -__test__ = {"API_TEST": """ -To all outward appearances, instances with deferred fields look the same as -normal instances when we examine attribute values. Therefore we test for the -number of deferred fields on returned instances (by poking at the internals), -as a way to observe what is going on. - ->>> s1 = Secondary.objects.create(first="x1", second="y1") ->>> p1 = Primary.objects.create(name="p1", value="xx", related=s1) - ->>> qs = Primary.objects.all() - ->>> count_delayed_fields(qs.defer('name')[0]) -1 ->>> count_delayed_fields(qs.only('name')[0]) -2 ->>> count_delayed_fields(qs.defer('related__first')[0]) -0 ->>> obj = qs.select_related().only('related__first')[0] ->>> count_delayed_fields(obj) -2 ->>> obj.related_id == s1.pk -True ->>> count_delayed_fields(qs.defer('name').extra(select={'a': 1})[0]) -1 ->>> count_delayed_fields(qs.extra(select={'a': 1}).defer('name')[0]) -1 ->>> count_delayed_fields(qs.defer('name').defer('value')[0]) -2 ->>> count_delayed_fields(qs.only('name').only('value')[0]) -2 ->>> count_delayed_fields(qs.only('name').defer('value')[0]) -2 ->>> count_delayed_fields(qs.only('name', 'value').defer('value')[0]) -2 ->>> count_delayed_fields(qs.defer('name').only('value')[0]) -2 ->>> obj = qs.only()[0] ->>> count_delayed_fields(qs.defer(None)[0]) -0 ->>> count_delayed_fields(qs.only('name').defer(None)[0]) -0 - -User values() won't defer anything (you get the full list of dictionaries -back), but it still works. ->>> qs.defer('name').values()[0] == {'id': p1.id, 'name': u'p1', 'value': 'xx', 'related_id': s1.id} -True ->>> qs.only('name').values()[0] == {'id': p1.id, 'name': u'p1', 'value': 'xx', 'related_id': s1.id} -True - -Using defer() and only() with get() is also valid. ->>> count_delayed_fields(qs.defer('name').get(pk=p1.pk)) -1 ->>> count_delayed_fields(qs.only('name').get(pk=p1.pk)) -2 - -# KNOWN NOT TO WORK: >>> count_delayed_fields(qs.only('name').select_related('related')[0]) -# KNOWN NOT TO WORK >>> count_delayed_fields(qs.defer('related').select_related('related')[0]) - -# Saving models with deferred fields is possible (but inefficient, since every -# field has to be retrieved first). - ->>> obj = Primary.objects.defer("value").get(name="p1") ->>> obj.name = "a new name" ->>> obj.save() ->>> Primary.objects.all() -[] - -# Regression for #10572 - A subclass with no extra fields can defer fields from the base class ->>> _ = Child.objects.create(name="c1", value="foo", related=s1) - -# You can defer a field on a baseclass when the subclass has no fields ->>> obj = Child.objects.defer("value").get(name="c1") ->>> count_delayed_fields(obj) -1 ->>> obj.name -u"c1" ->>> obj.value -u"foo" ->>> obj.name = "c2" ->>> obj.save() - -# You can retrive a single column on a base class with no fields ->>> obj = Child.objects.only("name").get(name="c2") ->>> count_delayed_fields(obj) -3 ->>> obj.name -u"c2" ->>> obj.value -u"foo" ->>> obj.name = "cc" ->>> obj.save() - ->>> _ = BigChild.objects.create(name="b1", value="foo", related=s1, other="bar") - -# You can defer a field on a baseclass ->>> obj = BigChild.objects.defer("value").get(name="b1") ->>> count_delayed_fields(obj) -1 ->>> obj.name -u"b1" ->>> obj.value -u"foo" ->>> obj.other -u"bar" ->>> obj.name = "b2" ->>> obj.save() - -# You can defer a field on a subclass ->>> obj = BigChild.objects.defer("other").get(name="b2") ->>> count_delayed_fields(obj) -1 ->>> obj.name -u"b2" ->>> obj.value -u"foo" ->>> obj.other -u"bar" ->>> obj.name = "b3" ->>> obj.save() - -# You can retrieve a single field on a baseclass ->>> obj = BigChild.objects.only("name").get(name="b3") ->>> count_delayed_fields(obj) -4 ->>> obj.name -u"b3" ->>> obj.value -u"foo" ->>> obj.other -u"bar" ->>> obj.name = "b4" ->>> obj.save() - -# You can retrieve a single field on a baseclass ->>> obj = BigChild.objects.only("other").get(name="b4") ->>> count_delayed_fields(obj) -4 ->>> obj.name -u"b4" ->>> obj.value -u"foo" ->>> obj.other -u"bar" ->>> obj.name = "bb" ->>> obj.save() - -"""} diff --git a/tests/modeltests/defer/tests.py b/tests/modeltests/defer/tests.py new file mode 100644 index 0000000000..5f6c53dee2 --- /dev/null +++ b/tests/modeltests/defer/tests.py @@ -0,0 +1,137 @@ +from django.db.models.query_utils import DeferredAttribute +from django.test import TestCase + +from models import Secondary, Primary, Child, BigChild + + +class DeferTests(TestCase): + def assert_delayed(self, obj, num): + count = 0 + for field in obj._meta.fields: + if isinstance(obj.__class__.__dict__.get(field.attname), + DeferredAttribute): + count += 1 + self.assertEqual(count, num) + + def test_defer(self): + # To all outward appearances, instances with deferred fields look the + # same as normal instances when we examine attribute values. Therefore + # we test for the number of deferred fields on returned instances (by + # poking at the internals), as a way to observe what is going on. + + s1 = Secondary.objects.create(first="x1", second="y1") + p1 = Primary.objects.create(name="p1", value="xx", related=s1) + + qs = Primary.objects.all() + + self.assert_delayed(qs.defer("name")[0], 1) + self.assert_delayed(qs.only("name")[0], 2) + self.assert_delayed(qs.defer("related__first")[0], 0) + + obj = qs.select_related().only("related__first")[0] + self.assert_delayed(obj, 2) + + self.assertEqual(obj.related_id, s1.pk) + + self.assert_delayed(qs.defer("name").extra(select={"a": 1})[0], 1) + self.assert_delayed(qs.extra(select={"a": 1}).defer("name")[0], 1) + self.assert_delayed(qs.defer("name").defer("value")[0], 2) + self.assert_delayed(qs.only("name").only("value")[0], 2) + self.assert_delayed(qs.only("name").defer("value")[0], 2) + self.assert_delayed(qs.only("name", "value").defer("value")[0], 2) + self.assert_delayed(qs.defer("name").only("value")[0], 2) + + obj = qs.only()[0] + self.assert_delayed(qs.defer(None)[0], 0) + self.assert_delayed(qs.only("name").defer(None)[0], 0) + + # User values() won't defer anything (you get the full list of + # dictionaries back), but it still works. + self.assertEqual(qs.defer("name").values()[0], { + "id": p1.id, + "name": "p1", + "value": "xx", + "related_id": s1.id, + }) + self.assertEqual(qs.only("name").values()[0], { + "id": p1.id, + "name": "p1", + "value": "xx", + "related_id": s1.id, + }) + + # Using defer() and only() with get() is also valid. + self.assert_delayed(qs.defer("name").get(pk=p1.pk), 1) + self.assert_delayed(qs.only("name").get(pk=p1.pk), 2) + + # DOES THIS WORK? + self.assert_delayed(qs.only("name").select_related("related")[0], 1) + self.assert_delayed(qs.defer("related").select_related("related")[0], 0) + + # Saving models with deferred fields is possible (but inefficient, + # since every field has to be retrieved first). + obj = Primary.objects.defer("value").get(name="p1") + obj.name = "a new name" + obj.save() + self.assertQuerysetEqual( + Primary.objects.all(), [ + "a new name", + ], + lambda p: p.name + ) + + # Regression for #10572 - A subclass with no extra fields can defer + # fields from the base class + Child.objects.create(name="c1", value="foo", related=s1) + # You can defer a field on a baseclass when the subclass has no fields + obj = Child.objects.defer("value").get(name="c1") + self.assert_delayed(obj, 1) + self.assertEqual(obj.name, "c1") + self.assertEqual(obj.value, "foo") + obj.name = "c2" + obj.save() + + # You can retrive a single column on a base class with no fields + obj = Child.objects.only("name").get(name="c2") + self.assert_delayed(obj, 3) + self.assertEqual(obj.name, "c2") + self.assertEqual(obj.value, "foo") + obj.name = "cc" + obj.save() + + BigChild.objects.create(name="b1", value="foo", related=s1, other="bar") + # You can defer a field on a baseclass + obj = BigChild.objects.defer("value").get(name="b1") + self.assert_delayed(obj, 1) + self.assertEqual(obj.name, "b1") + self.assertEqual(obj.value, "foo") + self.assertEqual(obj.other, "bar") + obj.name = "b2" + obj.save() + + # You can defer a field on a subclass + obj = BigChild.objects.defer("other").get(name="b2") + self.assert_delayed(obj, 1) + self.assertEqual(obj.name, "b2") + self.assertEqual(obj.value, "foo") + self.assertEqual(obj.other, "bar") + obj.name = "b3" + obj.save() + + # You can retrieve a single field on a baseclass + obj = BigChild.objects.only("name").get(name="b3") + self.assert_delayed(obj, 4) + self.assertEqual(obj.name, "b3") + self.assertEqual(obj.value, "foo") + self.assertEqual(obj.other, "bar") + obj.name = "b4" + obj.save() + + # You can retrieve a single field on a baseclass + obj = BigChild.objects.only("other").get(name="b4") + self.assert_delayed(obj, 4) + self.assertEqual(obj.name, "b4") + self.assertEqual(obj.value, "foo") + self.assertEqual(obj.other, "bar") + obj.name = "bb" + obj.save()