[1.2.X] Migrated defer doctests. Thanks to Alex Gaynor.

Backport of r13777 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@13794 bcc190cf-cafb-0310-a4f2-bffc1f526a37

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()
-[<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()
-
-"""}