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)