Проблема с фикстурами - UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte

class OrdersExportTestCase(TestCase):
    fixtures = [
        'products-fixture.json',
        'orders-fixture.json',
        'users-fixture.json'
    ]
 
    @classmethod
    def setUpClass(cls):
        super().setUpClass()
        cls.user = User.objects.create_user(username='test', password='test')
        cls.user.is_staff = True
        cls.user.save()
 
    def setUp(self) -> None:
        self.client.force_login(self.user)
 
    def test_get_orders_view(self):
        response = self.client.get(reverse(
            'shopapp:orders_export'
        ))
        self.assertEqual(response.status_code, 200)
        orders = Order.objects.order_by('pk').all()
        expected_data = [
            {
                'pk': order.pk,
                'delivery_address': order.delivery_address,
                'promocode': order.promocode,
                'user_id': order.user.pk,
                'products': [product.pk for product in order.products.all()]
            }
            for order in orders
        ]
        orders_data = response.json()
        self.assertEqual(orders_data['orders'], expected_data)
 
    @classmethod
    def tearDownClass(cls):
        cls.user.delete()

@method_decorator(user_passes_test(lambda u: u.is_staff), name='dispatch')
class OrdersExportView(View):
    def get(self, request: HttpRequest) -> JsonResponse:
        orders = Order.objects.order_by('pk').all()
        orders_data = [
            {
                'pk': order.pk,
                'delivery_address': order.delivery_address,
                'promocode': order.promocode,
                'user_id': order.user.pk,
                'products': [product.pk for product in order.products.all()]
            }
            for order in orders
        ]
 
        return JsonResponse({'orders': orders_data})

import json
 
with open('2.json', encoding='windows-1251') as f:
    data = json.load(f)
with open('1.json', 'w', encoding='utf-8') as f:
    json.dump(data, f, ensure_ascii=False)

class OrdersExportTestCase(TestCase):
    fixtures = [
        fixture_recode('products-fixture.json'),
        fixture_recode('orders-fixture.json'),
        fixture_recode('users-fixture.json')
    ]

def fixture_recode(fixture_name):
    recoded_fixture_name = fixture_name[:-5] + '-recoded.json'
 
    with open(f'shopapp/fixtures/{fixture_name}', encoding='windows-1251') as f:
        data = json.load(f)
    with open(f'shopapp/fixtures/{recoded_fixture_name}', 'w', encoding='utf-8') as f:
        json.dump(data, f, ensure_ascii=False)
 
    return recoded_fixture_name

[
  {
    "model": "shopapp.order",
    "pk": 1,
    "fields": {
      "delivery_address": "ul Street, d 11",
      "promocode": "SKILLBOX2023",
      "created_at": "2023-02-08T08:25:40.288Z",
      "user": 1,
      "products": [
        1,
        2
      ]
    }
  },
  {
    "model": "shopapp.order",
    "pk": 3,
    "fields": {
      "delivery_address": "ul. Melkaya, 44",
      "promocode": "CREATION123",
      "created_at": "2023-02-22T16:46:12.847Z",
      "user": 1,
      "products": [
        11
      ]
    }
  }
]