from __future__ import absolute_import import datetime from django.conf import settings from django.db import backend, transaction, DEFAULT_DB_ALIAS from django.test import TestCase, TransactionTestCase, skipUnlessDBFeature from .models import (Book, Award, AwardNote, Person, Child, Toy, PlayedWith, PlayedWithNote, Email, Researcher, Food, Eaten, Policy, Version, Location, Item, Image, File, Photo, FooFile, FooImage, FooPhoto, FooFileProxy) # Can't run this test under SQLite, because you can't # get two connections to an in-memory database. class DeleteLockingTest(TransactionTestCase): def setUp(self): # Create a second connection to the default database conn_settings = settings.DATABASES[DEFAULT_DB_ALIAS] self.conn2 = backend.DatabaseWrapper({ 'HOST': conn_settings['HOST'], 'NAME': conn_settings['NAME'], 'OPTIONS': conn_settings['OPTIONS'], 'PASSWORD': conn_settings['PASSWORD'], 'PORT': conn_settings['PORT'], 'USER': conn_settings['USER'], 'TIME_ZONE': settings.TIME_ZONE, }) # Put both DB connections into managed transaction mode transaction.enter_transaction_management() transaction.managed(True) self.conn2._enter_transaction_management(True) def tearDown(self): # Close down the second connection. transaction.leave_transaction_management() self.conn2.close() @skipUnlessDBFeature('test_db_allows_multiple_connections') def test_concurrent_delete(self): "Deletes on concurrent transactions don't collide and lock the database. Regression for #9479" # Create some dummy data b1 = Book(id=1, pagecount=100) b2 = Book(id=2, pagecount=200) b3 = Book(id=3, pagecount=300) b1.save() b2.save() b3.save() transaction.commit() self.assertEqual(3, Book.objects.count()) # Delete something using connection 2. cursor2 = self.conn2.cursor() cursor2.execute('DELETE from delete_regress_book WHERE id=1') self.conn2._commit() # Now perform a queryset delete that covers the object # deleted in connection 2. This causes an infinite loop # under MySQL InnoDB unless we keep track of already # deleted objects. Book.objects.filter(pagecount__lt=250).delete() transaction.commit() self.assertEqual(1, Book.objects.count()) transaction.commit() class DeleteCascadeTests(TestCase): def test_generic_relation_cascade(self): """ Django cascades deletes through generic-related objects to their reverse relations. """ person = Person.objects.create(name='Nelson Mandela') award = Award.objects.create(name='Nobel', content_object=person) note = AwardNote.objects.create(note='a peace prize', award=award) self.assertEqual(AwardNote.objects.count(), 1) person.delete() self.assertEqual(Award.objects.count(), 0) # first two asserts are just sanity checks, this is the kicker: self.assertEqual(AwardNote.objects.count(), 0) def test_fk_to_m2m_through(self): """ If an M2M relationship has an explicitly-specified through model, and some other model has an FK to that through model, deletion is cascaded from one of the participants in the M2M, to the through model, to its related model. """ juan = Child.objects.create(name='Juan') paints = Toy.objects.create(name='Paints') played = PlayedWith.objects.create(child=juan, toy=paints, date=datetime.date.today()) note = PlayedWithNote.objects.create(played=played, note='the next Jackson Pollock') self.assertEqual(PlayedWithNote.objects.count(), 1) paints.delete() self.assertEqual(PlayedWith.objects.count(), 0) # first two asserts just sanity checks, this is the kicker: self.assertEqual(PlayedWithNote.objects.count(), 0) def test_15776(self): policy = Policy.objects.create(pk=1, policy_number="1234") version = Version.objects.create(policy=policy) location = Location.objects.create(version=version) item = Item.objects.create(version=version, location=location) policy.delete() class DeleteCascadeTransactionTests(TransactionTestCase): def test_inheritance(self): """ Auto-created many-to-many through tables referencing a parent model are correctly found by the delete cascade when a child of that parent is deleted. Refs #14896. """ r = Researcher.objects.create() email = Email.objects.create( label="office-email", email_address="carl@science.edu" ) r.contacts.add(email) email.delete() def test_to_field(self): """ Cascade deletion works with ForeignKey.to_field set to non-PK. """ apple = Food.objects.create(name="apple") eaten = Eaten.objects.create(food=apple, meal="lunch") apple.delete() class LargeDeleteTests(TestCase): def test_large_deletes(self): "Regression for #13309 -- if the number of objects > chunk size, deletion still occurs" for x in range(300): track = Book.objects.create(pagecount=x+100) Book.objects.all().delete() self.assertEqual(Book.objects.count(), 0) class ProxyDeleteTest(TestCase): """ Tests on_delete behavior for proxy models. See #16128. """ def create_image(self): """Return an Image referenced by both a FooImage and a FooFile.""" # Create an Image test_image = Image() test_image.save() foo_image = FooImage(my_image=test_image) foo_image.save() # Get the Image instance as a File test_file = File.objects.get(pk=test_image.pk) foo_file = FooFile(my_file=test_file) foo_file.save() return test_image def test_delete_proxy(self): """ Deleting the *proxy* instance bubbles through to its non-proxy and *all* referring objects are deleted. """ self.create_image() Image.objects.all().delete() # An Image deletion == File deletion self.assertEqual(len(Image.objects.all()), 0) self.assertEqual(len(File.objects.all()), 0) # The Image deletion cascaded and *all* references to it are deleted. self.assertEqual(len(FooImage.objects.all()), 0) self.assertEqual(len(FooFile.objects.all()), 0) def test_delete_proxy_of_proxy(self): """ Deleting a proxy-of-proxy instance should bubble through to its proxy and non-proxy parents, deleting *all* referring objects. """ test_image = self.create_image() # Get the Image as a Photo test_photo = Photo.objects.get(pk=test_image.pk) foo_photo = FooPhoto(my_photo=test_photo) foo_photo.save() Photo.objects.all().delete() # A Photo deletion == Image deletion == File deletion self.assertEqual(len(Photo.objects.all()), 0) self.assertEqual(len(Image.objects.all()), 0) self.assertEqual(len(File.objects.all()), 0) # The Photo deletion should have cascaded and deleted *all* # references to it. self.assertEqual(len(FooPhoto.objects.all()), 0) self.assertEqual(len(FooFile.objects.all()), 0) self.assertEqual(len(FooImage.objects.all()), 0) def test_delete_concrete_parent(self): """ Deleting an instance of a concrete model should also delete objects referencing its proxy subclass. """ self.create_image() File.objects.all().delete() # A File deletion == Image deletion self.assertEqual(len(File.objects.all()), 0) self.assertEqual(len(Image.objects.all()), 0) # The File deletion should have cascaded and deleted *all* references # to it. self.assertEqual(len(FooFile.objects.all()), 0) self.assertEqual(len(FooImage.objects.all()), 0) def test_delete_proxy_pair(self): """ If a pair of proxy models are linked by an FK from one concrete parent to the other, deleting one proxy model cascade-deletes the other, and the deletion happens in the right order (not triggering an IntegrityError on databases unable to defer integrity checks). Refs #17918. """ # Create an Image (proxy of File) and FooFileProxy (proxy of FooFile, # which has an FK to File) image = Image.objects.create() as_file = File.objects.get(pk=image.pk) FooFileProxy.objects.create(my_file=as_file) Image.objects.all().delete() self.assertEqual(len(FooFileProxy.objects.all()), 0)