工厂男孩产生“超出最大递归深度”错误

Question

我想定义两个模型，Company和Package。每个Package只有一个Company，但一个Company可以有多个Packages。但是，每个公司只能有一个default_package（可以为空）。我的设置如下：

class Company(models.Model):
    default_package = models.OneToOneField(
        'dashboard.Package',
        on_delete=models.SET_NULL,
        blank=True,
        null=True,
        related_name='default_for_%(class)s')


class Package(models.Model):
    company = models.ForeignKey(Company, on_delete=models.CASCADE)

dashboard应用程序标签在哪里。

为了简化这些模型的测试，我使用factory_boy如下方式为它们创建了测试工厂：

import factory
from .models import Company, Package

class CompanyFactory(factory.Factory):
    class Meta:
        model = Company 

    default_package = factory.SubFactory('dashboard.test_factories.PackageFactory')


class PackageFactory(factory.Factory):
    class Meta:
        model = Package

    company = factory.SubFactory(CompanyFactory)

现在我正在尝试两个测试：

class DefaultPackageTest(TestCase):
    def test_1(self):
        company = Company.objects.create()

    def test_2(self):
        company = CompanyFactory()

第一个只是创建一个Company，而第二个尝试使用 做同样的事情CompanyFactory。

然而奇怪的是，第一个测试通过了，而第二个测试失败了：

  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/factory/builder.py", line 233, in recurse
    return builder.build(parent_step=self, force_sequence=force_sequence)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/factory/builder.py", line 272, in build
    step.resolve(pre)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/factory/builder.py", line 221, in resolve
    self.attributes[field_name] = getattr(self.stub, field_name)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/factory/builder.py", line 355, in __getattr__
    declaration = self.__declarations[name]
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/site-packages/factory/builder.py", line 121, in __getitem__
    context=self.contexts[key],
RecursionError: maximum recursion depth exceeded

----------------------------------------------------------------------
Ran 2 tests in 0.012s

FAILED (errors=1)
Destroying test database for alias 'default'...

知道为什么这不起作用吗？我相信我已经按照文档（http://factoryboy.readthedocs.io/en/latest/reference.html#circular-importsCompanyFactory ）提供了的子工厂的完整路径。

更新

看来这个用例是由 Factory Boy 的后代 hooks解决的。看起来很有希望的是RelatedFactory，给出了以下示例：

class CityFactory(factory.Factory):
    class Meta:
        model = City

    capital_of = None
    name = "Toronto"

class CountryFactory(factory.Factory):
    class Meta:
        model = Country

    lang = 'fr'
    capital_city = factory.RelatedFactory(CityFactory, 'capital_of', name="Paris")

在Python REPL中测试如下：

>>> france = CountryFactory()
>>> City.objects.get(capital_of=france)
<City: Paris>

然而，我很难将此示例应用于我的情况。（文档中没有City和模型的文本解释或代码并没有帮助）。Country看起来capital_city与我的情况类似default_package，所以我尝试将其变成RelatedFactory这样，

default_package = factory.RelatedFactory('dashboard.test_factories.PackageFactory')

但我仍然遇到同样的错误。

Answer 1

因此，我通过实现一个post_generation函数来实现这一点：

    class PackageFactory(factory.Factory):
        class Meta:
            model = Package

        company = factory.SubFactory('dashboard.test_factories.CompanyFactory')

    class CompanyFactory(factory.Factory):
        class Meta:
            model = Company 

        @factory.post_generation
        def default_package(self, create, _, **__):
            PackageFactory(company=self)

kwargcompany=self停止递归，并使用所需的默认包属性正确创建工厂。