以下是我尝试编写测试的视图：
class RestaurantsTreeView(generics.ListCreateAPIView):
serializer_class = RestarauntsTreeSerializer
def get_serializer_class(self):
from rest_framework import serializers
if self.request.method == 'GET':
return RestarauntsTreeSerializer
parent_choices = self.request.user.restaurants_set.filter(status=Restaurants.VISIBLE)
class NestedRestaurantDetailSerializer(serializers.ModelSerializer):
parent_id = serializers.RelatedField(queryset=parent_choices, allow_null=True, required=False)
class Meta:
model = Restaurants
fields = ("id", "name", "parent_id")
return NestedRestaurantDetailSerializer
以下是我尝试通过POST请求创建的模型：
from mptt.models import MPTTModel, TreeForeignKey
class Restaurants(MPTTModel):
name = models.CharField(max_length=255, blank=True, null=True)
parent = TreeForeignKey('self', null=True, blank=True, related_name='children', db_index=True)
class MPTTMeta:
order_insertion_by = ['name']
def __str__(self):
return self.name
最后我的测试：
class CreateRestaurantTestCase(TestCase):
def setUp(self):
self.user = UserFactory.create()
self.user.user_permissions.add(Permission.objects.get(codename='add_restaurants'))
self.client = APIClient()
self.client.force_authenticate(user=self.user)
def test_authorization_required(self):
response = self.client.post(reverse('api_v1:restaurants_list'), data={
"parent_id": None,
"name": "fake restaurant",
})
self.assertEqual(response.status_code, 401)
返回该错误：
Error
Traceback (most recent call last):
File "project/cafe/tests/api/test_restaurants.py", line 26, in test_required_fields
response = self.client.post(reverse('api_v1:restaurants_list'), data={})
File "env/lib/python3.5/site-packages/rest_framework/test.py", line 299, in post
path, data=data, format=format, content_type=content_type, **extra)
File "env/lib/python3.5/site-packages/rest_framework/test.py", line 212, in post
return self.generic('POST', path, data, content_type, **extra)
File "env/lib/python3.5/site-packages/rest_framework/test.py", line 237, in generic
method, path, data, content_type, secure, **extra)
File "env/lib/python3.5/site-packages/django/test/client.py", line 416, in generic
return self.request(**r)
File "env/lib/python3.5/site-packages/rest_framework/test.py", line 288, in request
return super(APIClient, self).request(**kwargs)
File "env/lib/python3.5/site-packages/rest_framework/test.py", line 240, in request
request = super(APIRequestFactory, self).request(**kwargs)
File "env/lib/python3.5/site-packages/django/test/client.py", line 501, in request
six.reraise(*exc_info)
File "env/lib/python3.5/site-packages/django/utils/six.py", line 686, in reraise
raise value
File "env/lib/python3.5/site-packages/django/core/handlers/exception.py", line 41, in inner
response = get_response(request)
File "env/lib/python3.5/site-packages/django/core/handlers/base.py", line 187, in _get_response
response = self.process_exception_by_middleware(e, request)
File "env/lib/python3.5/site-packages/django/core/handlers/base.py", line 185, in _get_response
response = wrapped_callback(request, *callback_args, **callback_kwargs)
File "env/lib/python3.5/site-packages/django/views/decorators/csrf.py", line 58, in wrapped_view
return view_func(*args, **kwargs)
File "env/lib/python3.5/site-packages/django/views/generic/base.py", line 68, in view
return self.dispatch(request, *args, **kwargs)
File "env/lib/python3.5/site-packages/rest_framework/views.py", line 489, in dispatch
response = self.handle_exception(exc)
File "env/lib/python3.5/site-packages/rest_framework/views.py", line 449, in handle_exception
self.raise_uncaught_exception(exc)
File "env/lib/python3.5/site-packages/rest_framework/views.py", line 486, in dispatch
response = handler(request, *args, **kwargs)
File "env/lib/python3.5/site-packages/rest_framework/generics.py", line 244, in post
return self.create(request, *args, **kwargs)
File "env/lib/python3.5/site-packages/rest_framework/mixins.py", line 21, in create
self.perform_create(serializer)
File "env/lib/python3.5/site-packages/rest_framework/mixins.py", line 26, in perform_create
serializer.save()
File "env/lib/python3.5/site-packages/rest_framework/serializers.py", line 214, in save
self.instance = self.create(validated_data)
File "env/lib/python3.5/site-packages/rest_framework/serializers.py", line 913, in create
instance = ModelClass.objects.create(**validated_data)
File "env/lib/python3.5/site-packages/django/db/models/manager.py", line 85, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "env/lib/python3.5/site-packages/django/db/models/query.py", line 394, in create
obj.save(force_insert=True, using=self.db)
File "env/lib/python3.5/site-packages/mptt/models.py", line 977, in save
right_sibling = opts.get_ordered_insertion_target(self, parent)
File "env/lib/python3.5/site-packages/mptt/models.py", line 216, in get_ordered_insertion_target
queryset = node.__class__._tree_manager.db_manager(node._state.db).filter(filters).order_by(*order_by)
File "env/lib/python3.5/site-packages/django/db/models/manager.py", line 85, in manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "env/lib/python3.5/site-packages/django/db/models/query.py", line 784, in filter
return self._filter_or_exclude(False, *args, **kwargs)
File "env/lib/python3.5/site-packages/django/db/models/query.py", line 802, in _filter_or_exclude
clone.query.add_q(Q(*args, **kwargs))
File "env/lib/python3.5/site-packages/django/db/models/sql/query.py", line 1250, in add_q
clause, _ = self._add_q(q_object, self.used_aliases)
File "env/lib/python3.5/site-packages/django/db/models/sql/query.py", line 1270, in _add_q
current_negated, allow_joins, split_subq)
File "env/lib/python3.5/site-packages/django/db/models/sql/query.py", line 1276, in _add_q
allow_joins=allow_joins, split_subq=split_subq,
File "env/lib/python3.5/site-packages/django/db/models/sql/query.py", line 1160, in build_filter
value, lookups, used_joins = self.prepare_lookup_value(value, lookups, can_reuse, allow_joins)
File "env/lib/python3.5/site-packages/django/db/models/sql/query.py", line 989, in prepare_lookup_value
raise ValueError("Cannot use None as a query value")
ValueError: Cannot use None as a query value
Destroying test database for alias 'default'...
Process finished with exit code 1
我希望能够创建具有空父字段的餐馆。它可以是没有父字段或带有空父字段的帖子。谢谢 django 1.11，drf 3.7，mptt 0.8.7
答案 0 :(得分：1)
首先，将序列化程序定义放在视图中会使代码不可读......您可以修改parent_id字段的查询集，同时覆盖视图中的get_serializer方法
# serializers.py
from rest_framework import serializers
class NestedRestaurantDetailSerializer(serializers.ModelSerializer):
# We don't care about filtering the queryset here, we override it in the view
parent_id = serializers.RelatedField(queryset=Restaurant.objects.all(), allow_null=True, required=False)
class Meta:
model = Restaurants
fields = ("id", "name", "parent_id")
# views.py
from .serializers import (
RestaurantsTreeSerializer,
NestedRestaurantDetailSerializer
)
class RestaurantsTreeView(generics.ListCreateAPIView):
def get_serializer(self, *args, **kwargs):
if self.request.method == 'GET':
kwargs['context'] = self.get_serializer_context()
return RestaurantsTreeSerializer(*args, **kwargs)
else:
kwargs['context'] = self.get_serializer_context()
nested_serializer = NestedRestaurantDetailSerializer(*args, **kwargs)
# Here we modify the queryset of the `parent_id` field
nested_serializer.fields['parent_id'].queryset = self.request.user.restaurants_set.filter(status=Restaurants.VISIBLE)
return nested_serializer
其次，关于您的例外，在documentation of django-mptt中，您可以阅读以下内容：
<强> order_insertion_by
字段名称列表，应该在插入新树节点或重新构建现有节点时定义排序，首先是最重要的排序字段名称。默认为[]。
假设任何标识为定义排序的字段在数据库中永远不会为NULL。
重要的一条就在上面。在您的模型定义中，您有：
name = models.CharField(max_length=255, blank=True, null=True)
您可以将可空字段定义为order_insertion_by属性的参数。您的最终例外是Cannot use None as a query value这一事实让我觉得它已经联系起来......
未显示异常来源的测试方法的代码，但我假设您使用test_required_fields之类的名称尝试向您的enpoint发送空name参数。因此Cannot use None as a query value。由于您在模型中将name字段定义为nullable，因此序列化程序也会将其标记为nullable。