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django - 如何解决 factory_boy SubFactory 调用中的 CyclicDefinitionError？

问题描述

我有以下型号

# in ModelA_App/models.py
class ModelA(models.Model):
    TYPEA = 1
    TYPEB = 2
    TYPE_CHOICES = (
       (TYPEA, 'TypeA'),
       (TYPEB, 'TypeB')
    )
    type = models.PositiveSmallIntegerField(choices=TYPE_CHOICES)
    name - models.CharField(max_length = 100)

#in ModelB_App/models.py
from ModelA_App.models import ModelA

class ModelB(models.Model):
    label = models.TextFiled()
    model_a = models.OneToOneField(ModelA, on_delete=models.CASCADE)

我有以下工厂：

#in ModelA_App/factories.py
class ModelAFactory(factory.django.DjangoModelFactory):
    class Meta:
       model = ModelA

    name = factory.Faker('word')
    type = ModelA.TYPEA

#in ModelB_App/factories.py
from ModelA_App.models import ModelA
from ModelA_App.factories import ModelAFactory

class ModelBFactory(factory.django.DjangoModelFactory):
    class Meta:
       model = ModelB

    label = factory.Faker('text')
    model_a = SubFactory(ModelAFactory, type = factory.LazyAttribute(lambda o: '%d' % o.type))

    class Params:
       type = ModelA.TYPEA

我希望能够创建ModelB具有ModelA. TYPEB尝试行ModelBFactory.create(type = ModelA.TYPEB) 会导致错误：

factory.errors.CyclicDefinitionError: 'type' 的循环惰性属性定义；在 ['type'] 中找到循环

此外，当我type在课堂上将名称更改Params为例如model_type具有：

model_a = SubFactory(ModelAFactory, type = factory.LazyAttribute(lambda o: '%d' % o.model_type))

它失败了

AttributeError：参数“model_type”未知。

我怎样才能实现我的目标？

标签： djangofactory-boy

解决方案

当您编写 aSubFactory时，您提供的附加定义将锚定到该子工厂。你写的相当于：

class SubModelAFactory(ModelAFactory):
    class Meta:
        # Not required - implied by class inheritance
        model = models.ModelA

    type = factory.LazyAttribute(lambda o: '%d' % o.type)

class ModelBFactory(factory.django.DjangoModelFactory):
    ...
    model_a = factory.SubFactory(SubModelFactory)

相反，您应该“提升”一个级别，如文档中所述SelfAttribute：

class ModelBFactory(factory.django.DjangoModelFactory):
    ...
    model_a = factory.SubFactory(
        SubModelFactory,
        type=factory.LazyAttribute(lambda o: '%d' % o.factory_parent.type),

        # If the value can be passed without conversion, use:
        type=factory.SelfAttribute('..type'),
    )

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