Migrated defer doctests. Thanks to Alex Gaynor.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13777 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Russell Keith-Magee 2010-09-12 20:03:20 +00:00
parent 1d50f6af99
commit eb8b5dc2d4
2 changed files with 138 additions and 163 deletions

View File

@ -3,7 +3,7 @@ Tests for defer() and only().
""" """
from django.db import models from django.db import models
from django.db.models.query_utils import DeferredAttribute
class Secondary(models.Model): class Secondary(models.Model):
first = models.CharField(max_length=50) first = models.CharField(max_length=50)
@ -22,165 +22,3 @@ class Child(Primary):
class BigChild(Primary): class BigChild(Primary):
other = models.CharField(max_length=50) 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()
[<Primary: a new 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")
>>> 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()
"""}

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@ -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()