Factory Boy subfactory over 'self'

Question

Does anyone know how to create the factory in factoryboy based on this models.py

class Halte(models.Model):

    koppel_halte1 = models.ForeignKey('self',
                                  related_name='koppel_halteA',
                                  verbose_name="Koppel Halte",
                                  help_text="geef hier een gekoppelde halte aan",
                                  null=True, blank=True)

    koppel_halte2 = models.ForeignKey('self',
                                  related_name='koppel_halteB',
                                  verbose_name="Koppel Halte",
                                  help_text="geef hier een gekoppelde halte aan",
                                  null=True, blank=True)

Notice the 'self'? (And YES this type of relation is necesarry.)

I have tried several things in FactoryBoy (SubFactory, RelatedFactory, SelfAtribute, PostGeneration) but I can't get it to work.

one of the attempts in a factories.py

class HalteFactoryA(factory.DjangoModelFactory):
    class Meta:
        model = models.Halte


class HalteFactoryB(factory.DjangoModelFactory):
    class Meta:
        model = models.Halte


class HalteFactory(factory.DjangoModelFactory):
    class Meta:
        model = models.Halte
    # todo: how to do this?? (see models.Halte)
    koppel_halte1 = factory.RelatedFactory(HalteFactoryA)
    koppel_halte2 = factory.RelatedFactory(HalteFactoryB)

Any advice?

Thank you.

Answer 1

@bakkal has it mostly right, but an important missing factor is that a target recursion depth must be specified, as stated in this issue: https://github.com/rbarrois/factory_boy/issues/173

# myproj/myapp/factories.py
class MyModelFactory(factory.Factory):
    class Meta:
        model = models.MyModel
    parent = factory.SubFactory('myapp.factories.MyModelFactory')

Then a recursion max depth needs to be added, or you get the infinite depth reached error (as noted by @Sjoerd van Poelgeest in the comments):

m = MyModelFactory(parent__parent__parent__parent=None)

In This case we are allowing a depth of 3 being created, and the last one will have a null parent.

Answer 2

Fully qualified model name in the model FK

To make it easier on the tools to introspect your model, instead of 'self', use the fully qualified model name:

koppel_halte1 = models.ForeignKey('yourapp.Halte', ...)
koppel_halte2 = models.ForeignKey('yourapp.Halte', ...)

Notice it's a string 'yourapp.Halte' and not yourapp.Halte.

Fully qualified factory name in the SubFactory

If you insist on using 'self' in the model you can use the fully qualified model name in your SubFactory

# yourapp/factories.py

class HalteFactory(factory.Factory):
    class Meta:
        model = yourapp.Halte

    koppel_halte1 = factory.SubFactory('yourapp.factories.HalteFactory')
    koppel_halte2 = factory.SubFactory('yourapp.factories.HalteFactory')