test_generic_relations.py

from django.test import TestCase

from rest_framework import serializers

from .models import Bookmark, Note, Tag


class TestGenericRelations(TestCase):
    def setUp(self):
        self.bookmark = Bookmark.objects.create(url='https://www.djangoproject.com/')
        Tag.objects.create(tagged_item=self.bookmark, tag='django')
        Tag.objects.create(tagged_item=self.bookmark, tag='python')
        self.note = Note.objects.create(text='Remember the milk')
        Tag.objects.create(tagged_item=self.note, tag='reminder')

    def test_generic_relation(self):
        """
        Test a relationship that spans a GenericRelation field.
        IE. A reverse generic relationship.
        """

        class BookmarkSerializer(serializers.ModelSerializer):
            tags = serializers.StringRelatedField(many=True)

            class Meta:
                model = Bookmark
                fields = ('tags', 'url')

        serializer = BookmarkSerializer(self.bookmark)
        expected = {
            'tags': ['django', 'python'],
            'url': 'https://www.djangoproject.com/'
        }
        assert serializer.data == expected

    def test_generic_fk(self):
        """
        Test a relationship that spans a GenericForeignKey field.
        IE. A forward generic relationship.
        """

        class TagSerializer(serializers.ModelSerializer):
            tagged_item = serializers.StringRelatedField()

            class Meta:
                model = Tag
                fields = ('tag', 'tagged_item')

        serializer = TagSerializer(Tag.objects.all(), many=True)
        expected = [
            {
                'tag': 'django',
                'tagged_item': 'Bookmark: https://www.djangoproject.com/'
            },
            {
                'tag': 'python',
                'tagged_item': 'Bookmark: https://www.djangoproject.com/'
            },
            {
                'tag': 'reminder',
                'tagged_item': 'Note: Remember the milk'
            }
        ]
        assert serializer.data == expected