django/tests/contenttypes_tests/test_models.py

from django.apps import apps
from django.contrib.contenttypes.models import ContentType, ContentTypeManager
from django.contrib.contenttypes.prefetch import GenericPrefetch
from django.db import models
from django.db.migrations.state import ModelState, ProjectState
from django.test import TestCase, override_settings
from django.test.utils import isolate_apps

from .models import Author, ConcreteModel, FooWithUrl, ProxyModel


class ContentTypesTests(TestCase):
    def setUp(self):
        ContentType.objects.clear_cache()
        self.addCleanup(ContentType.objects.clear_cache)

    def test_lookup_cache(self):
        """
        The content type cache (see ContentTypeManager) works correctly.
        Lookups for a particular content type -- by model, ID, or natural key
        -- should hit the database only on the first lookup.
        """
        # At this point, a lookup for a ContentType should hit the DB
        with self.assertNumQueries(1):
            ContentType.objects.get_for_model(ContentType)

        # A second hit, though, won't hit the DB, nor will a lookup by ID
        # or natural key
        with self.assertNumQueries(0):
            ct = ContentType.objects.get_for_model(ContentType)
        with self.assertNumQueries(0):
            ContentType.objects.get_for_id(ct.id)
        with self.assertNumQueries(0):
            ContentType.objects.get_by_natural_key("contenttypes", "contenttype")

        # Once we clear the cache, another lookup will again hit the DB
        ContentType.objects.clear_cache()
        with self.assertNumQueries(1):
            ContentType.objects.get_for_model(ContentType)

        # The same should happen with a lookup by natural key
        ContentType.objects.clear_cache()
        with self.assertNumQueries(1):
            ContentType.objects.get_by_natural_key("contenttypes", "contenttype")
        # And a second hit shouldn't hit the DB
        with self.assertNumQueries(0):
            ContentType.objects.get_by_natural_key("contenttypes", "contenttype")

    def test_get_for_models_creation(self):
        ContentType.objects.all().delete()
        with self.assertNumQueries(4):
            cts = ContentType.objects.get_for_models(
                ContentType, FooWithUrl, ProxyModel, ConcreteModel
            )
        self.assertEqual(
            cts,
            {
                ContentType: ContentType.objects.get_for_model(ContentType),
                FooWithUrl: ContentType.objects.get_for_model(FooWithUrl),
                ProxyModel: ContentType.objects.get_for_model(ProxyModel),
                ConcreteModel: ContentType.objects.get_for_model(ConcreteModel),
            },
        )

    def test_get_for_models_empty_cache(self):
        # Empty cache.
        with self.assertNumQueries(1):
            cts = ContentType.objects.get_for_models(
                ContentType, FooWithUrl, ProxyModel, ConcreteModel
            )
        self.assertEqual(
            cts,
            {
                ContentType: ContentType.objects.get_for_model(ContentType),
                FooWithUrl: ContentType.objects.get_for_model(FooWithUrl),
                ProxyModel: ContentType.objects.get_for_model(ProxyModel),
                ConcreteModel: ContentType.objects.get_for_model(ConcreteModel),
            },
        )

    def test_get_for_models_partial_cache(self):
        # Partial cache
        ContentType.objects.get_for_model(ContentType)
        with self.assertNumQueries(1):
            cts = ContentType.objects.get_for_models(ContentType, FooWithUrl)
        self.assertEqual(
            cts,
            {
                ContentType: ContentType.objects.get_for_model(ContentType),
                FooWithUrl: ContentType.objects.get_for_model(FooWithUrl),
            },
        )

    def test_get_for_models_migrations(self):
        state = ProjectState.from_apps(apps.get_app_config("contenttypes"))
        ContentType = state.apps.get_model("contenttypes", "ContentType")
        cts = ContentType.objects.get_for_models(ContentType)
        self.assertEqual(
            cts, {ContentType: ContentType.objects.get_for_model(ContentType)}
        )

    @isolate_apps("contenttypes_tests")
    def test_get_for_models_migrations_create_model(self):
        state = ProjectState.from_apps(apps.get_app_config("contenttypes"))

        class Foo(models.Model):
            class Meta:
                app_label = "contenttypes_tests"

        state.add_model(ModelState.from_model(Foo))
        ContentType = state.apps.get_model("contenttypes", "ContentType")
        cts = ContentType.objects.get_for_models(FooWithUrl, Foo)
        self.assertEqual(
            cts,
            {
                Foo: ContentType.objects.get_for_model(Foo),
                FooWithUrl: ContentType.objects.get_for_model(FooWithUrl),
            },
        )

    def test_get_for_models_full_cache(self):
        # Full cache
        ContentType.objects.get_for_model(ContentType)
        ContentType.objects.get_for_model(FooWithUrl)
        with self.assertNumQueries(0):
            cts = ContentType.objects.get_for_models(ContentType, FooWithUrl)
        self.assertEqual(
            cts,
            {
                ContentType: ContentType.objects.get_for_model(ContentType),
                FooWithUrl: ContentType.objects.get_for_model(FooWithUrl),
            },
        )

    @isolate_apps("contenttypes_tests")
    def test_get_for_model_create_contenttype(self):
        """
        ContentTypeManager.get_for_model() creates the corresponding content
        type if it doesn't exist in the database.
        """

        class ModelCreatedOnTheFly(models.Model):
            name = models.CharField()

        ct = ContentType.objects.get_for_model(ModelCreatedOnTheFly)
        self.assertEqual(ct.app_label, "contenttypes_tests")
        self.assertEqual(ct.model, "modelcreatedonthefly")
        self.assertEqual(str(ct), "modelcreatedonthefly")

    def test_get_for_concrete_model(self):
        """
        Make sure the `for_concrete_model` kwarg correctly works
        with concrete, proxy and deferred models
        """
        concrete_model_ct = ContentType.objects.get_for_model(ConcreteModel)
        self.assertEqual(
            concrete_model_ct, ContentType.objects.get_for_model(ProxyModel)
        )
        self.assertEqual(
            concrete_model_ct,
            ContentType.objects.get_for_model(ConcreteModel, for_concrete_model=False),
        )

        proxy_model_ct = ContentType.objects.get_for_model(
            ProxyModel, for_concrete_model=False
        )
        self.assertNotEqual(concrete_model_ct, proxy_model_ct)

        # Make sure deferred model are correctly handled
        ConcreteModel.objects.create(name="Concrete")
        DeferredConcreteModel = ConcreteModel.objects.only("pk").get().__class__
        DeferredProxyModel = ProxyModel.objects.only("pk").get().__class__

        self.assertEqual(
            concrete_model_ct, ContentType.objects.get_for_model(DeferredConcreteModel)
        )
        self.assertEqual(
            concrete_model_ct,
            ContentType.objects.get_for_model(
                DeferredConcreteModel, for_concrete_model=False
            ),
        )
        self.assertEqual(
            concrete_model_ct, ContentType.objects.get_for_model(DeferredProxyModel)
        )
        self.assertEqual(
            proxy_model_ct,
            ContentType.objects.get_for_model(
                DeferredProxyModel, for_concrete_model=False
            ),
        )

    def test_get_for_concrete_models(self):
        """
        Make sure the `for_concrete_models` kwarg correctly works
        with concrete, proxy and deferred models.
        """
        concrete_model_ct = ContentType.objects.get_for_model(ConcreteModel)

        cts = ContentType.objects.get_for_models(ConcreteModel, ProxyModel)
        self.assertEqual(
            cts,
            {
                ConcreteModel: concrete_model_ct,
                ProxyModel: concrete_model_ct,
            },
        )

        proxy_model_ct = ContentType.objects.get_for_model(
            ProxyModel, for_concrete_model=False
        )
        cts = ContentType.objects.get_for_models(
            ConcreteModel, ProxyModel, for_concrete_models=False
        )
        self.assertEqual(
            cts,
            {
                ConcreteModel: concrete_model_ct,
                ProxyModel: proxy_model_ct,
            },
        )

        # Make sure deferred model are correctly handled
        ConcreteModel.objects.create(name="Concrete")
        DeferredConcreteModel = ConcreteModel.objects.only("pk").get().__class__
        DeferredProxyModel = ProxyModel.objects.only("pk").get().__class__

        cts = ContentType.objects.get_for_models(
            DeferredConcreteModel, DeferredProxyModel
        )
        self.assertEqual(
            cts,
            {
                DeferredConcreteModel: concrete_model_ct,
                DeferredProxyModel: concrete_model_ct,
            },
        )

        cts = ContentType.objects.get_for_models(
            DeferredConcreteModel, DeferredProxyModel, for_concrete_models=False
        )
        self.assertEqual(
            cts,
            {
                DeferredConcreteModel: concrete_model_ct,
                DeferredProxyModel: proxy_model_ct,
            },
        )

    def test_cache_not_shared_between_managers(self):
        with self.assertNumQueries(1):
            ContentType.objects.get_for_model(ContentType)
        with self.assertNumQueries(0):
            ContentType.objects.get_for_model(ContentType)
        other_manager = ContentTypeManager()
        other_manager.model = ContentType
        with self.assertNumQueries(1):
            other_manager.get_for_model(ContentType)
        with self.assertNumQueries(0):
            other_manager.get_for_model(ContentType)

    def test_missing_model(self):
        """
        Displaying content types in admin (or anywhere) doesn't break on
        leftover content type records in the DB for which no model is defined
        anymore.
        """
        ct = ContentType.objects.create(
            app_label="contenttypes",
            model="OldModel",
        )
        self.assertEqual(str(ct), "OldModel")
        self.assertIsNone(ct.model_class())

        # Stale ContentTypes can be fetched like any other object.
        ct_fetched = ContentType.objects.get_for_id(ct.pk)
        self.assertIsNone(ct_fetched.model_class())

    def test_missing_model_with_existing_model_name(self):
        """
        Displaying content types in admin (or anywhere) doesn't break on
        leftover content type records in the DB for which no model is defined
        anymore, even if a model with the same name exists in another app.
        """
        # Create a stale ContentType that matches the name of an existing
        # model.
        ContentType.objects.create(app_label="contenttypes", model="author")
        ContentType.objects.clear_cache()
        # get_for_models() should work as expected for existing models.
        cts = ContentType.objects.get_for_models(ContentType, Author)
        self.assertEqual(
            cts,
            {
                ContentType: ContentType.objects.get_for_model(ContentType),
                Author: ContentType.objects.get_for_model(Author),
            },
        )

    def test_str(self):
        ct = ContentType.objects.get(app_label="contenttypes_tests", model="site")
        self.assertEqual(str(ct), "Contenttypes_Tests | site")

    def test_str_auth(self):
        ct = ContentType.objects.get(app_label="auth", model="group")
        self.assertEqual(str(ct), "Authentication and Authorization | group")

    def test_name(self):
        ct = ContentType.objects.get(app_label="contenttypes_tests", model="site")
        self.assertEqual(ct.name, "site")

    def test_app_labeled_name(self):
        ct = ContentType.objects.get(app_label="contenttypes_tests", model="site")
        self.assertEqual(ct.app_labeled_name, "Contenttypes_Tests | site")

    def test_name_unknown_model(self):
        ct = ContentType(app_label="contenttypes_tests", model="unknown")
        self.assertEqual(ct.name, "unknown")

    def test_app_labeled_name_unknown_model(self):
        ct = ContentType(app_label="contenttypes_tests", model="unknown")
        self.assertEqual(ct.app_labeled_name, "unknown")


class TestRouter:
    def db_for_read(self, model, **hints):
        return "other"

    def db_for_write(self, model, **hints):
        return "default"

    def allow_relation(self, obj1, obj2, **hints):
        return True


@override_settings(DATABASE_ROUTERS=[TestRouter()])
class ContentTypesMultidbTests(TestCase):
    databases = {"default", "other"}

    def test_multidb(self):
        """
        When using multiple databases, ContentType.objects.get_for_model() uses
        db_for_read().
        """
        ContentType.objects.clear_cache()
        with (
            self.assertNumQueries(0, using="default"),
            self.assertNumQueries(1, using="other"),
        ):
            ContentType.objects.get_for_model(Author)


class GenericPrefetchTests(TestCase):
    def test_querysets_required(self):
        msg = (
            "GenericPrefetch.__init__() missing 1 required "
            "positional argument: 'querysets'"
        )
        with self.assertRaisesMessage(TypeError, msg):
            GenericPrefetch("question")

    def test_values_queryset(self):
        msg = "Prefetch querysets cannot use raw(), values(), and values_list()."
        with self.assertRaisesMessage(ValueError, msg):
            GenericPrefetch("question", [Author.objects.values("pk")])
        with self.assertRaisesMessage(ValueError, msg):
            GenericPrefetch("question", [Author.objects.values_list("pk")])

    def test_raw_queryset(self):
        msg = "Prefetch querysets cannot use raw(), values(), and values_list()."
        with self.assertRaisesMessage(ValueError, msg):
            GenericPrefetch("question", [Author.objects.raw("select pk from author")])