Allow functions as models

[instanceofmel]

Hi,

in our project, we're using factories for our models:

# domain/factories.py
from . import model, events

def item_factory(sku: str, price: float):
    obj = model.Item(sku, price)
    obj.events.append(events.ItemCreated())
    return obj

Now, in our tests we want factory boy to call those factories instead of the model classes directly, which works perfectly except in this case:

# tests/factories.py
class ItemFactory(factory.Factory):
    class Meta:
        model = factories.item_factory
    sku = ...
    price = ...

class SpecialItemFactory(ItemFactory):  # Inherits from the factory above
    sku = "special"

When a factory inherits from another factory, FactoryOptions._get_counter_reference expects the assigned model to be a class, because issubclass raises:

TypeError: issubclass() arg 1 must be a class

We couldn't find a fix for this case so I've opened this PR. If my solution is wrong or if anything is missing in my commit, please don't hesitate to let me know.

BR

[rbarrois]

Hello,

Thanks for the feedback! That's indeed likely to be a bug.

Would it be possible to have a minimal example of code where this breaks, to add to our test suite?

NB: This is one of the reasons why I prefer to see an issue first, before jumping in the code — our issue templates make it easier for us to gather all details we need to move forward ;)

[instanceofmel]

Hey, sorry for the late reply. You mean something like this?

import factory


class Item:
    def __init__(self, sku, price):
        self.sku = sku
        self.price = price


def item_factory(sku, price):
    obj = model.Item(sku, price)
    return obj


class ItemFactory(factory.Factory):
    class Meta:
        model = item_factory

    sku = "foo"
    price = "bar"


class SpecialItemFactory(ItemFactory):
    sku = "special"


item = SpecialItemFactory()  # TypeError: issubclass() arg 1 must be a class

Should I add a test case to the test suite?

BR

[rbarrois]

Yes please! That's exactly what I had in mind ;)

[instanceofmel]

Done @rbarrois

[instanceofmel]

@rbarrois Could you please merge this when you have a chance? Thank you.

[instanceofmel]

Hi @rbarrois, let me know if there's anything left to do for me in order to get this merged 🙏