如何解决 factory_boy SubFactory 调用中的 CyclicDefinitionError？

Question

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

我希望能够使用 ModelA 和 TYPEB 创建 ModelB 对象。 试行ModelBFactory.create(type = ModelA.TYPEB) 导致错误：

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

此外，当我将 type 类中的 type 名称更改为例如model_type 有：

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

失败了

AttributeError：参数“model_type”未知。

我怎样才能实现我的目标？

Answer 1

当您编写SubFactory 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“升级”一个级别，如 the SelfAttribute docs 中所述：

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'),
    )

Answer 2

我找到了解决方案。 ModelBFactory 应该是这样的：

#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 = factory.LazyAttribute(lambda o: ModelAFactory(type = o.type))

    class Params:
       type = ModelA.TYPEA

我没有将ModelAFactory 属性作为LazyAttribute 而是将整个工厂作为一个。