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from __future__ import absolute_import
from operator import attrgetter
from django.core.exceptions import FieldError
from django.test import TestCase
from .models import (Chef, CommonInfo, ItalianRestaurant, ParkingLot, Place,
Post, Restaurant, Student, StudentWorker, Supplier, Worker, MixinModel)
class ModelInheritanceTests(TestCase):
def test_abstract(self):
# The Student and Worker models both have 'name' and 'age' fields on
# them and inherit the __unicode__() method, just as with normal Python
# subclassing. This is useful if you want to factor out common
# information for programming purposes, but still completely
# independent separate models at the database level.
w1 = Worker.objects.create(name="Fred", age=35, job="Quarry worker")
w2 = Worker.objects.create(name="Barney", age=34, job="Quarry worker")
s = Student.objects.create(name="Pebbles", age=5, school_class="1B")
self.assertEqual(unicode(w1), "Worker Fred")
self.assertEqual(unicode(s), "Student Pebbles")
# The children inherit the Meta class of their parents (if they don't
# specify their own).
self.assertQuerysetEqual(
Worker.objects.values("name"), [
{"name": "Barney"},
{"name": "Fred"},
],
lambda o: o
)
# Since Student does not subclass CommonInfo's Meta, it has the effect
# of completely overriding it. So ordering by name doesn't take place
# for Students.
self.assertEqual(Student._meta.ordering, [])
# However, the CommonInfo class cannot be used as a normal model (it
# doesn't exist as a model).
self.assertRaises(AttributeError, lambda: CommonInfo.objects.all())
# A StudentWorker which does not exist is both a Student and Worker
# which does not exist.
self.assertRaises(Student.DoesNotExist,
StudentWorker.objects.get, pk=12321321
)
self.assertRaises(Worker.DoesNotExist,
StudentWorker.objects.get, pk=12321321
)
# MultipleObjectsReturned is also inherited.
# This is written out "long form", rather than using __init__/create()
# because of a bug with diamond inheritance (#10808)
sw1 = StudentWorker()
sw1.name = "Wilma"
sw1.age = 35
sw1.save()
sw2 = StudentWorker()
sw2.name = "Betty"
sw2.age = 24
sw2.save()
self.assertRaises(Student.MultipleObjectsReturned,
StudentWorker.objects.get, pk__lt=sw2.pk + 100
)
self.assertRaises(Worker.MultipleObjectsReturned,
StudentWorker.objects.get, pk__lt=sw2.pk + 100
)
def test_multiple_table(self):
post = Post.objects.create(title="Lorem Ipsum")
# The Post model has distinct accessors for the Comment and Link models.
post.attached_comment_set.create(content="Save $ on V1agr@", is_spam=True)
post.attached_link_set.create(
content="The Web framework for perfections with deadlines.",
url="http://www.djangoproject.com/"
)
# The Post model doesn't have an attribute called
# 'attached_%(class)s_set'.
self.assertRaises(AttributeError,
getattr, post, "attached_%(class)s_set"
)
# The Place/Restaurant/ItalianRestaurant models all exist as
# independent models. However, the subclasses also have transparent
# access to the fields of their ancestors.
# Create a couple of Places.
p1 = Place.objects.create(name="Master Shakes", address="666 W. Jersey")
p2 = Place.objects.create(name="Ace Harware", address="1013 N. Ashland")
# Test constructor for Restaurant.
r = Restaurant.objects.create(
name="Demon Dogs",
address="944 W. Fullerton",
serves_hot_dogs=True,
serves_pizza=False,
rating=2
)
# Test the constructor for ItalianRestaurant.
c = Chef.objects.create(name="Albert")
ir = ItalianRestaurant.objects.create(
name="Ristorante Miron",
address="1234 W. Ash",
serves_hot_dogs=False,
serves_pizza=False,
serves_gnocchi=True,
rating=4,
chef=c
)
self.assertQuerysetEqual(
ItalianRestaurant.objects.filter(address="1234 W. Ash"), [
"Ristorante Miron",
],
attrgetter("name")
)
ir.address = "1234 W. Elm"
ir.save()
self.assertQuerysetEqual(
ItalianRestaurant.objects.filter(address="1234 W. Elm"), [
"Ristorante Miron",
],
attrgetter("name")
)
# Make sure Restaurant and ItalianRestaurant have the right fields in
# the right order.
self.assertEqual(
[f.name for f in Restaurant._meta.fields],
["id", "name", "address", "place_ptr", "rating", "serves_hot_dogs", "serves_pizza", "chef"]
)
self.assertEqual(
[f.name for f in ItalianRestaurant._meta.fields],
["id", "name", "address", "place_ptr", "rating", "serves_hot_dogs", "serves_pizza", "chef", "restaurant_ptr", "serves_gnocchi"],
)
self.assertEqual(Restaurant._meta.ordering, ["-rating"])
# Even though p.supplier for a Place 'p' (a parent of a Supplier), a
# Restaurant object cannot access that reverse relation, since it's not
# part of the Place-Supplier Hierarchy.
self.assertQuerysetEqual(Place.objects.filter(supplier__name="foo"), [])
self.assertRaises(FieldError,
Restaurant.objects.filter, supplier__name="foo"
)
# Parent fields can be used directly in filters on the child model.
self.assertQuerysetEqual(
Restaurant.objects.filter(name="Demon Dogs"), [
"Demon Dogs",
],
attrgetter("name")
)
self.assertQuerysetEqual(
ItalianRestaurant.objects.filter(address="1234 W. Elm"), [
"Ristorante Miron",
],
attrgetter("name")
)
# Filters against the parent model return objects of the parent's type.
p = Place.objects.get(name="Demon Dogs")
self.assertIs(type(p), Place)
# Since the parent and child are linked by an automatically created
# OneToOneField, you can get from the parent to the child by using the
# child's name.
self.assertEqual(
p.restaurant, Restaurant.objects.get(name="Demon Dogs")
)
self.assertEqual(
Place.objects.get(name="Ristorante Miron").restaurant.italianrestaurant,
ItalianRestaurant.objects.get(name="Ristorante Miron")
)
self.assertEqual(
Restaurant.objects.get(name="Ristorante Miron").italianrestaurant,
ItalianRestaurant.objects.get(name="Ristorante Miron")
)
# This won't work because the Demon Dogs restaurant is not an Italian
# restaurant.
self.assertRaises(ItalianRestaurant.DoesNotExist,
lambda: p.restaurant.italianrestaurant
)
# An ItalianRestaurant which does not exist is also a Place which does
# not exist.
self.assertRaises(Place.DoesNotExist,
ItalianRestaurant.objects.get, name="The Noodle Void"
)
# MultipleObjectsReturned is also inherited.
self.assertRaises(Place.MultipleObjectsReturned,
Restaurant.objects.get, id__lt=12321
)
# Related objects work just as they normally do.
s1 = Supplier.objects.create(name="Joe's Chickens", address="123 Sesame St")
s1.customers = [r, ir]
s2 = Supplier.objects.create(name="Luigi's Pasta", address="456 Sesame St")
s2.customers = [ir]
# This won't work because the Place we select is not a Restaurant (it's
# a Supplier).
p = Place.objects.get(name="Joe's Chickens")
self.assertRaises(Restaurant.DoesNotExist,
lambda: p.restaurant
)
self.assertEqual(p.supplier, s1)
self.assertQuerysetEqual(
ir.provider.order_by("-name"), [
"Luigi's Pasta",
"Joe's Chickens"
],
attrgetter("name")
)
self.assertQuerysetEqual(
Restaurant.objects.filter(provider__name__contains="Chickens"), [
"Ristorante Miron",
"Demon Dogs",
],
attrgetter("name")
)
self.assertQuerysetEqual(
ItalianRestaurant.objects.filter(provider__name__contains="Chickens"), [
"Ristorante Miron",
],
attrgetter("name"),
)
park1 = ParkingLot.objects.create(
name="Main St", address="111 Main St", main_site=s1
)
park2 = ParkingLot.objects.create(
name="Well Lit", address="124 Sesame St", main_site=ir
)
self.assertEqual(
Restaurant.objects.get(lot__name="Well Lit").name,
"Ristorante Miron"
)
# The update() command can update fields in parent and child classes at
# once (although it executed multiple SQL queries to do so).
rows = Restaurant.objects.filter(
serves_hot_dogs=True, name__contains="D"
).update(
name="Demon Puppies", serves_hot_dogs=False
)
self.assertEqual(rows, 1)
r1 = Restaurant.objects.get(pk=r.pk)
self.assertFalse(r1.serves_hot_dogs)
self.assertEqual(r1.name, "Demon Puppies")
# The values() command also works on fields from parent models.
self.assertQuerysetEqual(
ItalianRestaurant.objects.values("name", "rating"), [
{"rating": 4, "name": "Ristorante Miron"}
],
lambda o: o
)
# select_related works with fields from the parent object as if they
# were a normal part of the model.
self.assertNumQueries(2,
lambda: ItalianRestaurant.objects.all()[0].chef
)
self.assertNumQueries(1,
lambda: ItalianRestaurant.objects.select_related("chef")[0].chef
)
def test_mixin_init(self):
m = MixinModel()
self.assertEqual(m.other_attr, 1)
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