fix: set lowercase for verbose name strings

shop/tests/test_api_products.py

@@ -22,7 +22,7 @@ class TestProductsAPI(APITestCase, TestUserAuthenticationMixin):
         self.tag = Tag.objects.create(name="Alimentos")
 
     def get_random_sku(self):
-        return ''.join(random.choices(string.ascii_uppercase, k=16))
+        return "".join(random.choices(string.ascii_uppercase, k=16))
 
     def create_products(self):
         self.product = Product.objects.create(

shop/tests/test_shop_models.py

@@ -14,17 +14,17 @@ class ShopModelsTest(TestCase):
 
     def create_products(self):
         self.potatoes = Product.objects.create(
-            sku='0000001',
+            sku="0000001",
             name="Patatas",
             stock=Decimal("100.00"),
         )
         self.gasoline = Product.objects.create(
-            sku='0000002',
+            sku="0000002",
             name="Gasolina",
             stock=Decimal("800.00"),
         )
         self.usb_c = Product.objects.create(
-            sku='0000003',
+            sku="0000003",
             name="Cable USB-C",
             stock=Decimal("5.00"),
         )