django/tests/model_inheritance/tests.py

import unittest
from operator import attrgetter

from django.core.exceptions import FieldError, ValidationError
from django.db import connection, models
from django.test import SimpleTestCase, TestCase
from django.test.utils import CaptureQueriesContext, isolate_apps
from django.utils.version import PY36

from .models import (
    Base, Chef, CommonInfo, GrandChild, GrandParent, ItalianRestaurant,
    MixinModel, ParkingLot, Place, Post, Restaurant, Student, SubBase,
    Supplier, Title, Worker,
)


class ModelInheritanceTests(TestCase):
    def test_abstract(self):
        # The Student and Worker models both have 'name' and 'age' fields on
        # them and inherit the __str__() 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")
        Worker.objects.create(name="Barney", age=34, job="Quarry worker")

        s = Student.objects.create(name="Pebbles", age=5, school_class="1B")

        self.assertEqual(str(w1), "Worker Fred")
        self.assertEqual(str(s), "Student Pebbles")

        # The children inherit the Meta class of their parents (if they don't
        # specify their own).
        self.assertSequenceEqual(
            Worker.objects.values("name"), [
                {"name": "Barney"},
                {"name": "Fred"},
            ],
        )

        # 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).
        with self.assertRaisesMessage(AttributeError, "'CommonInfo' has no attribute 'objects'"):
            CommonInfo.objects.all()

    def test_reverse_relation_for_different_hierarchy_tree(self):
        # 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"), [])
        msg = (
            "Cannot resolve keyword 'supplier' into field. Choices are: "
            "address, chef, chef_id, id, italianrestaurant, lot, name, "
            "place_ptr, place_ptr_id, provider, rating, serves_hot_dogs, serves_pizza"
        )
        with self.assertRaisesMessage(FieldError, msg):
            Restaurant.objects.filter(supplier__name="foo")

    def test_model_with_distinct_accessors(self):
        # The Post model has distinct accessors for the Comment and Link models.
        post = Post.objects.create(title="Lorem Ipsum")
        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'.
        msg = "'Post' object has no attribute 'attached_%(class)s_set'"
        with self.assertRaisesMessage(AttributeError, msg):
            getattr(post, "attached_%(class)s_set")

    def test_model_with_distinct_related_query_name(self):
        self.assertQuerysetEqual(Post.objects.filter(attached_model_inheritance_comments__is_spam=True), [])

        # The Post model doesn't have a related query accessor based on
        # related_name (attached_comment_set).
        msg = "Cannot resolve keyword 'attached_comment_set' into field."
        with self.assertRaisesMessage(FieldError, msg):
            Post.objects.filter(attached_comment_set__is_spam=True)

    def test_meta_fields_and_ordering(self):
        # 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"])

    def test_custompk_m2m(self):
        b = Base.objects.create()
        b.titles.add(Title.objects.create(title="foof"))
        s = SubBase.objects.create(sub_id=b.id)
        b = Base.objects.get(pk=s.id)
        self.assertNotEqual(b.pk, s.pk)
        # Low-level test for related_val
        self.assertEqual(s.titles.related_val, (s.id,))
        # Higher level test for correct query values (title foof not
        # accidentally found).
        self.assertQuerysetEqual(s.titles.all(), [])

    def test_update_parent_filtering(self):
        """
        Updating a field of a model subclass doesn't issue an UPDATE
        query constrained by an inner query (#10399).
        """
        supplier = Supplier.objects.create(
            name='Central market',
            address='610 some street',
        )
        # Capture the expected query in a database agnostic way
        with CaptureQueriesContext(connection) as captured_queries:
            Place.objects.filter(pk=supplier.pk).update(name=supplier.name)
        expected_sql = captured_queries[0]['sql']
        # Capture the queries executed when a subclassed model instance is saved.
        with CaptureQueriesContext(connection) as captured_queries:
            supplier.save(update_fields=('name',))
        for query in captured_queries:
            sql = query['sql']
            if 'UPDATE' in sql:
                self.assertEqual(expected_sql, sql)

    def test_create_child_no_update(self):
        """Creating a child with non-abstract parents only issues INSERTs."""
        def a():
            GrandChild.objects.create(
                email='grand_parent@example.com',
                first_name='grand',
                last_name='parent',
            )

        def b():
            GrandChild().save()
        for i, test in enumerate([a, b]):
            with self.subTest(i=i), self.assertNumQueries(4), CaptureQueriesContext(connection) as queries:
                test()
                for query in queries:
                    sql = query['sql']
                    self.assertIn('INSERT INTO', sql, sql)

    def test_eq(self):
        # Equality doesn't transfer in multitable inheritance.
        self.assertNotEqual(Place(id=1), Restaurant(id=1))
        self.assertNotEqual(Restaurant(id=1), Place(id=1))

    def test_mixin_init(self):
        m = MixinModel()
        self.assertEqual(m.other_attr, 1)

    @isolate_apps('model_inheritance')
    def test_abstract_parent_link(self):
        class A(models.Model):
            pass

        class B(A):
            a = models.OneToOneField('A', parent_link=True, on_delete=models.CASCADE)

            class Meta:
                abstract = True

        class C(B):
            pass

        self.assertIs(C._meta.parents[A], C._meta.get_field('a'))

    @unittest.skipUnless(PY36, 'init_subclass is new in Python 3.6')
    @isolate_apps('model_inheritance')
    def test_init_subclass(self):
        saved_kwargs = {}

        class A:
            def __init_subclass__(cls, **kwargs):
                super().__init_subclass__()
                saved_kwargs.update(kwargs)

        kwargs = {'x': 1, 'y': 2, 'z': 3}

        class B(A, models.Model, **kwargs):
            pass

        self.assertEqual(saved_kwargs, kwargs)


class ModelInheritanceDataTests(TestCase):
    @classmethod
    def setUpTestData(cls):
        cls.restaurant = Restaurant.objects.create(
            name="Demon Dogs",
            address="944 W. Fullerton",
            serves_hot_dogs=True,
            serves_pizza=False,
            rating=2,
        )

        chef = Chef.objects.create(name="Albert")
        cls.italian_restaurant = ItalianRestaurant.objects.create(
            name="Ristorante Miron",
            address="1234 W. Ash",
            serves_hot_dogs=False,
            serves_pizza=False,
            serves_gnocchi=True,
            rating=4,
            chef=chef,
        )

    def test_filter_inherited_model(self):
        self.assertQuerysetEqual(
            ItalianRestaurant.objects.filter(address="1234 W. Ash"), [
                "Ristorante Miron",
            ],
            attrgetter("name")
        )

    def test_update_inherited_model(self):
        self.italian_restaurant.address = "1234 W. Elm"
        self.italian_restaurant.save()
        self.assertQuerysetEqual(
            ItalianRestaurant.objects.filter(address="1234 W. Elm"), [
                "Ristorante Miron",
            ],
            attrgetter("name")
        )

    def test_parent_fields_available_for_filtering_in_child_model(self):
        # 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. Ash"), [
                "Ristorante Miron",
            ],
            attrgetter("name")
        )

    def test_filter_on_parent_returns_object_of_parent_type(self):
        # Filters against the parent model return objects of the parent's type.
        p = Place.objects.get(name="Demon Dogs")
        self.assertIs(type(p), Place)

    def test_parent_child_one_to_one_link(self):
        # 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(
            Place.objects.get(name="Demon Dogs").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")
        )

    def test_parent_child_one_to_one_link_on_nonrelated_objects(self):
        # This won't work because the Demon Dogs restaurant is not an Italian
        # restaurant.
        with self.assertRaises(ItalianRestaurant.DoesNotExist):
            Place.objects.get(name="Demon Dogs").restaurant.italianrestaurant

    def test_inherited_does_not_exist_exception(self):
        # An ItalianRestaurant which does not exist is also a Place which does
        # not exist.
        with self.assertRaises(Place.DoesNotExist):
            ItalianRestaurant.objects.get(name="The Noodle Void")

    def test_inherited_multiple_objects_returned_exception(self):
        # MultipleObjectsReturned is also inherited.
        with self.assertRaises(Place.MultipleObjectsReturned):
            Restaurant.objects.get()

    def test_related_objects_for_inherited_models(self):
        # Related objects work just as they normally do.
        s1 = Supplier.objects.create(name="Joe's Chickens", address="123 Sesame St")
        s1.customers .set([self.restaurant, self.italian_restaurant])
        s2 = Supplier.objects.create(name="Luigi's Pasta", address="456 Sesame St")
        s2.customers.set([self.italian_restaurant])

        # 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")
        with self.assertRaises(Restaurant.DoesNotExist):
            p.restaurant

        self.assertEqual(p.supplier, s1)
        self.assertQuerysetEqual(
            self.italian_restaurant.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"),
        )

        ParkingLot.objects.create(
            name="Main St", address="111 Main St", main_site=s1
        )
        ParkingLot.objects.create(
            name="Well Lit", address="124 Sesame St", main_site=self.italian_restaurant
        )

        self.assertEqual(
            Restaurant.objects.get(lot__name="Well Lit").name,
            "Ristorante Miron"
        )

    def test_update_works_on_parent_and_child_models_at_once(self):
        # 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=self.restaurant.pk)
        self.assertFalse(r1.serves_hot_dogs)
        self.assertEqual(r1.name, "Demon Puppies")

    def test_values_works_on_parent_model_fields(self):
        # The values() command also works on fields from parent models.
        self.assertSequenceEqual(
            ItalianRestaurant.objects.values("name", "rating"), [
                {"rating": 4, "name": "Ristorante Miron"},
            ],
        )

    def test_select_related_works_on_parent_model_fields(self):
        # 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_select_related_defer(self):
        """
        #23370 - Should be able to defer child fields when using
        select_related() from parent to child.
        """
        qs = (Restaurant.objects.select_related("italianrestaurant")
              .defer("italianrestaurant__serves_gnocchi").order_by("rating"))

        # The field was actually deferred
        with self.assertNumQueries(2):
            objs = list(qs.all())
            self.assertTrue(objs[1].italianrestaurant.serves_gnocchi)

        # Model fields where assigned correct values
        self.assertEqual(qs[0].name, 'Demon Dogs')
        self.assertEqual(qs[0].rating, 2)
        self.assertEqual(qs[1].italianrestaurant.name, 'Ristorante Miron')
        self.assertEqual(qs[1].italianrestaurant.rating, 4)

    def test_parent_cache_reuse(self):
        place = Place.objects.create()
        GrandChild.objects.create(place=place)
        grand_parent = GrandParent.objects.latest('pk')
        with self.assertNumQueries(1):
            self.assertEqual(grand_parent.place, place)
        parent = grand_parent.parent
        with self.assertNumQueries(0):
            self.assertEqual(parent.place, place)
        child = parent.child
        with self.assertNumQueries(0):
            self.assertEqual(child.place, place)
        grandchild = child.grandchild
        with self.assertNumQueries(0):
            self.assertEqual(grandchild.place, place)

    def test_update_query_counts(self):
        """
        Update queries do not generate unnecessary queries (#18304).
        """
        with self.assertNumQueries(3):
            self.italian_restaurant.save()

    def test_filter_inherited_on_null(self):
        # Refs #12567
        Supplier.objects.create(
            name="Central market",
            address="610 some street",
        )
        self.assertQuerysetEqual(
            Place.objects.filter(supplier__isnull=False), [
                "Central market",
            ],
            attrgetter("name")
        )
        self.assertQuerysetEqual(
            Place.objects.filter(supplier__isnull=True).order_by("name"), [
                "Demon Dogs",
                "Ristorante Miron",
            ],
            attrgetter("name")
        )

    def test_exclude_inherited_on_null(self):
        # Refs #12567
        Supplier.objects.create(
            name="Central market",
            address="610 some street",
        )
        self.assertQuerysetEqual(
            Place.objects.exclude(supplier__isnull=False).order_by("name"), [
                "Demon Dogs",
                "Ristorante Miron",
            ],
            attrgetter("name")
        )
        self.assertQuerysetEqual(
            Place.objects.exclude(supplier__isnull=True), [
                "Central market",
            ],
            attrgetter("name")
        )


@isolate_apps('model_inheritance', 'model_inheritance.tests')
class InheritanceSameModelNameTests(SimpleTestCase):
    def test_abstract_fk_related_name(self):
        related_name = '%(app_label)s_%(class)s_references'

        class Referenced(models.Model):
            class Meta:
                app_label = 'model_inheritance'

        class AbstractReferent(models.Model):
            reference = models.ForeignKey(Referenced, models.CASCADE, related_name=related_name)

            class Meta:
                app_label = 'model_inheritance'
                abstract = True

        class Referent(AbstractReferent):
            class Meta:
                app_label = 'model_inheritance'

        LocalReferent = Referent

        class Referent(AbstractReferent):
            class Meta:
                app_label = 'tests'

        ForeignReferent = Referent

        self.assertFalse(hasattr(Referenced, related_name))
        self.assertIs(Referenced.model_inheritance_referent_references.field.model, LocalReferent)
        self.assertIs(Referenced.tests_referent_references.field.model, ForeignReferent)


class InheritanceUniqueTests(TestCase):
    @classmethod
    def setUpTestData(cls):
        cls.grand_parent = GrandParent.objects.create(
            email='grand_parent@example.com',
            first_name='grand',
            last_name='parent',
        )

    def test_unique(self):
        grand_child = GrandChild(
            email=self.grand_parent.email,
            first_name='grand',
            last_name='child',
        )
        msg = 'Grand parent with this Email already exists.'
        with self.assertRaisesMessage(ValidationError, msg):
            grand_child.validate_unique()

    def test_unique_together(self):
        grand_child = GrandChild(
            email='grand_child@example.com',
            first_name=self.grand_parent.first_name,
            last_name=self.grand_parent.last_name,
        )
        msg = 'Grand parent with this First name and Last name already exists.'
        with self.assertRaisesMessage(ValidationError, msg):
            grand_child.validate_unique()