'Both `pk` and the actual primary key name are valid in `Meta.fields`.'

def test_pk_fields(self):

    class TestSerializer(serializers.ModelSerializer, ):
        class Meta:
            model = RegularFieldsModel
            fields = (u'pk', u'auto_field')
    expected = dedent(u"\n                                                TestSerializer():\n                                                                pk    =    IntegerField(label='Auto    field',    read_only=True)\n                                                                auto_field    =    IntegerField(read_only=True)\n                                ")
    self.assertEqual(repr(TestSerializer()), expected)
