Viewing github.com/django/django-stable-4.1.x/tests/select

from django.core.exceptions import FieldError

from django.test import SimpleTestCase, TestCase

```
from .models import (
```
```
    Bookmark,
```
```
    Domain,
```
```
    Family,
```
```
    Genus,
```
```
    HybridSpecies,
```
```
    Kingdom,
```
```
    Klass,
```
```
    Order,
```
```
    Phylum,
```
```
    Pizza,
```
```
    Species,
```
```
    TaggedItem,
```
```
)
```
```
class SelectRelatedTests(TestCase):
```
```
    @classmethod
```
```
    def create_tree(cls, stringtree):
```
```
        """
```

        Helper to create a complete tree.

```
        """
```
```
        names = stringtree.split()
```

        models = [Domain, Kingdom, Phylum, Klass, Order, Family, Genus, Species]

        assert len(names) == len(models), (names, models)

```
        parent = None
```

        for name, model in zip(names, models):

```
            try:
```

                obj = model.objects.get(name=name)

```
            except model.DoesNotExist:
```
```
                obj = model(name=name)
```
```
            if parent:
```

                setattr(obj, parent.__class__.__name__.lower(), parent)

```
            obj.save()
```
```
            parent = obj
```
```
    @classmethod
```
```
    def setUpTestData(cls):
```
```
        cls.create_tree(
```

            "Eukaryota Animalia Anthropoda Insecta Diptera Drosophilidae Drosophila "

```
            "melanogaster"
```
```
        )
```
```
        cls.create_tree(
```

            "Eukaryota Animalia Chordata Mammalia Primates Hominidae Homo sapiens"

```
        )
```
```
        cls.create_tree(
```

            "Eukaryota Plantae Magnoliophyta Magnoliopsida Fabales Fabaceae Pisum "

```
            "sativum"
```
```
        )
```
```
        cls.create_tree(
```

            "Eukaryota Fungi Basidiomycota Homobasidiomycatae Agaricales Amanitacae "

```
            "Amanita muscaria"
```
```
        )
```

    def test_access_fks_without_select_related(self):

```
        """
```

        Normally, accessing FKs doesn't fill in related objects

```
        """
```
```
        with self.assertNumQueries(8):
```

            fly = Species.objects.get(name="melanogaster")

            domain = fly.genus.family.order.klass.phylum.kingdom.domain

            self.assertEqual(domain.name, "Eukaryota")

    def test_access_fks_with_select_related(self):

```
        """
```

        A select_related() call will fill in those related objects without any

```
        extra queries
```
```
        """
```
```
        with self.assertNumQueries(1):
```

            person = Species.objects.select_related(

                "genus__family__order__klass__phylum__kingdom__domain"

```
            ).get(name="sapiens")
```

            domain = person.genus.family.order.klass.phylum.kingdom.domain

            self.assertEqual(domain.name, "Eukaryota")

    def test_list_without_select_related(self):

```
        with self.assertNumQueries(9):
```

            world = Species.objects.all()

            families = [o.genus.family.name for o in world]

```
            self.assertEqual(
```
```
                sorted(families),
```
```
                [
```
```
                    "Amanitacae",
```
```
                    "Drosophilidae",
```
```
                    "Fabaceae",
```
```
                    "Hominidae",
```
```
                ],
```
```
            )
```

    def test_list_with_select_related(self):

        """select_related() applies to entire lists, not just items."""

```
        with self.assertNumQueries(1):
```

            world = Species.objects.select_related()

            families = [o.genus.family.name for o in world]

```
            self.assertEqual(
```
```
                sorted(families),
```
```
                [
```
```
                    "Amanitacae",
```
```
                    "Drosophilidae",
```
```
                    "Fabaceae",
```
```
                    "Hominidae",
```
```
                ],
```
```
            )
```
```
    def test_list_with_depth(self):
```
```
        """
```

        Passing a relationship field lookup specifier to select_related() will

        stop the descent at a particular level. This can be used on lists as

```
        well.
```
```
        """
```
```
        with self.assertNumQueries(5):
```

            world = Species.objects.select_related("genus__family")

            orders = [o.genus.family.order.name for o in world]

```
            self.assertEqual(
```

                sorted(orders), ["Agaricales", "Diptera", "Fabales", "Primates"]

```
            )
```

    def test_select_related_with_extra(self):

```
        s = (
```
```
            Species.objects.all()
```
```
            .select_related()
```

            .extra(select={"a": "select_related_species.id + 10"})[0]

```
        )
```

        self.assertEqual(s.id + 10, s.a)

```
    def test_certain_fields(self):
```
```
        """
```

        The optional fields passed to select_related() control which related

        models we pull in. This allows for smaller queries.

        In this case, we explicitly say to select the 'genus' and

        'genus.family' models, leading to the same number of queries as before.

```
        """
```
```
        with self.assertNumQueries(1):
```

            world = Species.objects.select_related("genus__family")

            families = [o.genus.family.name for o in world]

```
            self.assertEqual(
```
```
                sorted(families),
```

                ["Amanitacae", "Drosophilidae", "Fabaceae", "Hominidae"],

```
            )
```

    def test_more_certain_fields(self):

```
        """
```

        In this case, we explicitly say to select the 'genus' and

        'genus.family' models, leading to the same number of queries as before.

```
        """
```
```
        with self.assertNumQueries(2):
```

            world = Species.objects.filter(genus__name="Amanita").select_related(

```
                "genus__family"
```
```
            )
```

            orders = [o.genus.family.order.name for o in world]

            self.assertEqual(orders, ["Agaricales"])

```
    def test_field_traversal(self):
```
```
        with self.assertNumQueries(1):
```
```
            s = (
```
```
                Species.objects.all()
```

                .select_related("genus__family__order")

```
                .order_by("id")[0:1]
```
```
                .get()
```

                .genus.family.order.name

```
            )
```

            self.assertEqual(s, "Diptera")

```
    def test_none_clears_list(self):
```

        queryset = Species.objects.select_related("genus").select_related(None)

        self.assertIs(queryset.query.select_related, False)

```
    def test_chaining(self):
```

        parent_1, parent_2 = Species.objects.all()[:2]

```
        HybridSpecies.objects.create(
```

            name="hybrid", parent_1=parent_1, parent_2=parent_2

```
        )
```

        queryset = HybridSpecies.objects.select_related("parent_1").select_related(

```
            "parent_2"
```
```
        )
```
```
        with self.assertNumQueries(1):
```
```
            obj = queryset[0]
```

            self.assertEqual(obj.parent_1, parent_1)

            self.assertEqual(obj.parent_2, parent_2)

    def test_reverse_relation_caching(self):

```
        species = (
```

            Species.objects.select_related("genus").filter(name="melanogaster").first()

```
        )
```
```
        with self.assertNumQueries(0):
```

            self.assertEqual(species.genus.name, "Drosophila")

        # The species_set reverse relation isn't cached.

        self.assertEqual(species.genus._state.fields_cache, {})

```
        with self.assertNumQueries(1):
```

            self.assertEqual(species.genus.species_set.first().name, "melanogaster")

    def test_select_related_after_values(self):

```
        """
```

        Running select_related() after calling values() raises a TypeError

```
        """
```

        message = "Cannot call select_related() after .values() or .values_list()"

        with self.assertRaisesMessage(TypeError, message):

            list(Species.objects.values("name").select_related("genus"))

    def test_select_related_after_values_list(self):

```
        """
```

        Running select_related() after calling values_list() raises a TypeError

```
        """
```

        message = "Cannot call select_related() after .values() or .values_list()"

        with self.assertRaisesMessage(TypeError, message):

            list(Species.objects.values_list("name").select_related("genus"))

class SelectRelatedValidationTests(SimpleTestCase):

```
    """
```

    select_related() should thrown an error on fields that do not exist and

```
    non-relational fields.
```
```
    """
```
```
    non_relational_error = (
```

        "Non-relational field given in select_related: '%s'. Choices are: %s"

```
    )
```
```
    invalid_error = (
```

        "Invalid field name(s) given in select_related: '%s'. Choices are: %s"

```
    )
```

    def test_non_relational_field(self):

```
        with self.assertRaisesMessage(
```

            FieldError, self.non_relational_error % ("name", "genus")

```
        ):
```

            list(Species.objects.select_related("name__some_field"))

```
        with self.assertRaisesMessage(
```

            FieldError, self.non_relational_error % ("name", "genus")

```
        ):
```

            list(Species.objects.select_related("name"))

```
        with self.assertRaisesMessage(
```

            FieldError, self.non_relational_error % ("name", "(none)")

```
        ):
```

            list(Domain.objects.select_related("name"))

    def test_non_relational_field_nested(self):

```
        with self.assertRaisesMessage(
```

            FieldError, self.non_relational_error % ("name", "family")

```
        ):
```

            list(Species.objects.select_related("genus__name"))

```
    def test_many_to_many_field(self):
```
```
        with self.assertRaisesMessage(
```

            FieldError, self.invalid_error % ("toppings", "(none)")

```
        ):
```

            list(Pizza.objects.select_related("toppings"))

    def test_reverse_relational_field(self):

```
        with self.assertRaisesMessage(
```

            FieldError, self.invalid_error % ("child_1", "genus")

```
        ):
```

            list(Species.objects.select_related("child_1"))

```
    def test_invalid_field(self):
```
```
        with self.assertRaisesMessage(
```

            FieldError, self.invalid_error % ("invalid_field", "genus")

```
        ):
```

            list(Species.objects.select_related("invalid_field"))

```
        with self.assertRaisesMessage(
```

            FieldError, self.invalid_error % ("related_invalid_field", "family")

```
        ):
```

            list(Species.objects.select_related("genus__related_invalid_field"))

```
        with self.assertRaisesMessage(
```

            FieldError, self.invalid_error % ("invalid_field", "(none)")

```
        ):
```

            list(Domain.objects.select_related("invalid_field"))

```
    def test_generic_relations(self):
```

        with self.assertRaisesMessage(FieldError, self.invalid_error % ("tags", "")):

            list(Bookmark.objects.select_related("tags"))

```
        with self.assertRaisesMessage(
```

            FieldError, self.invalid_error % ("content_object", "content_type")

```
        ):
```

            list(TaggedItem.objects.select_related("content_object"))