django/tests/field_subclassing/tests.py

from __future__ import unicode_literals

import inspect

from django.core import exceptions, serializers
from django.db import connection
from django.test import SimpleTestCase, TestCase

from .fields import CustomTypedField, Small
from .models import ChoicesModel, DataModel, MyModel, OtherModel


class CustomField(TestCase):
    def test_refresh(self):
        d = DataModel.objects.create(data=[1, 2, 3])
        d.refresh_from_db(fields=['data'])
        self.assertIsInstance(d.data, list)
        self.assertEqual(d.data, [1, 2, 3])

    def test_defer(self):
        d = DataModel.objects.create(data=[1, 2, 3])

        self.assertIsInstance(d.data, list)

        d = DataModel.objects.get(pk=d.pk)
        self.assertIsInstance(d.data, list)
        self.assertEqual(d.data, [1, 2, 3])

        d = DataModel.objects.defer("data").get(pk=d.pk)
        self.assertIsInstance(d.data, list)
        self.assertEqual(d.data, [1, 2, 3])
        # Refetch for save
        d = DataModel.objects.defer("data").get(pk=d.pk)
        d.save()

        d = DataModel.objects.get(pk=d.pk)
        self.assertIsInstance(d.data, list)
        self.assertEqual(d.data, [1, 2, 3])

    def test_custom_field(self):
        # Creating a model with custom fields is done as per normal.
        s = Small(1, 2)
        self.assertEqual(str(s), "12")

        m = MyModel.objects.create(name="m", data=s)
        # Custom fields still have normal field's attributes.
        self.assertEqual(m._meta.get_field("data").verbose_name, "small field")

        # The m.data attribute has been initialized correctly. It's a Small
        # object.
        self.assertEqual((m.data.first, m.data.second), (1, 2))

        # The data loads back from the database correctly and 'data' has the
        # right type.
        m1 = MyModel.objects.get(pk=m.pk)
        self.assertIsInstance(m1.data, Small)
        self.assertEqual(str(m1.data), "12")

        # We can do normal filtering on the custom field (and will get an error
        # when we use a lookup type that does not make sense).
        s1 = Small(1, 3)
        s2 = Small("a", "b")
        self.assertQuerysetEqual(
            MyModel.objects.filter(data__in=[s, s1, s2]), [
                "m",
            ],
            lambda m: m.name,
        )
        self.assertRaises(TypeError, lambda: MyModel.objects.filter(data__lt=s))

        # Serialization works, too.
        stream = serializers.serialize("json", MyModel.objects.all())
        self.assertJSONEqual(stream, [{
            "pk": m1.pk,
            "model": "field_subclassing.mymodel",
            "fields": {"data": "12", "name": "m"}
        }])

        obj = list(serializers.deserialize("json", stream))[0]
        self.assertEqual(obj.object, m)

        # Test retrieving custom field data
        m.delete()

        m1 = MyModel.objects.create(name="1", data=Small(1, 2))
        MyModel.objects.create(name="2", data=Small(2, 3))

        self.assertQuerysetEqual(
            MyModel.objects.all(), [
                "12",
                "23",
            ],
            lambda m: str(m.data),
            ordered=False
        )

    def test_field_subclassing(self):
        o = OtherModel.objects.create(data=Small("a", "b"))
        o = OtherModel.objects.get()
        self.assertEqual(o.data.first, "a")
        self.assertEqual(o.data.second, "b")

    def test_subfieldbase_plays_nice_with_module_inspect(self):
        """
        Custom fields should play nice with python standard module inspect.

        http://users.rcn.com/python/download/Descriptor.htm#properties
        """
        # Even when looking for totally different properties, SubfieldBase's
        # non property like behavior made inspect crash. Refs #12568.
        data = dict(inspect.getmembers(MyModel))
        self.assertIn('__module__', data)
        self.assertEqual(data['__module__'], 'field_subclassing.models')

    def test_validation_of_choices_for_custom_field(self):
        # a valid choice
        o = ChoicesModel.objects.create(data=Small('a', 'b'))
        o.full_clean()

        # an invalid choice
        o = ChoicesModel.objects.create(data=Small('d', 'e'))
        with self.assertRaises(exceptions.ValidationError):
            o.full_clean()


class TestDbType(SimpleTestCase):

    def test_db_parameters_respects_db_type(self):
        f = CustomTypedField()
        self.assertEqual(f.db_parameters(connection)['type'], 'custom_field')