UserWarning: UserWarning: Using a <class 'list'> as model type for <ListFactory for <class 'list'>> is discouraged

The following simplified example, adjusted from the factoryboy documentation:

import factory
from pytest_factoryboy import register


class User:
    def __init__(self, flags):
        self.flags = flags


@register
class UserFactory(factory.Factory):
    class Meta:
        model = User

    flags = factory.List(["a", "b", "c"])


def test_example(user_factory):
    user = user_factory.build()
    assert user.flags == ["a", "b", "c"]

produces the warning:

UserWarning: Using a <class 'list'> as model type for <ListFactory for <class 'list'>> is discouraged by pytest-factoryboy, as it assumes that the model name is 'list' when using it as SubFactory or RelatedFactory, which is too generic and probably not what you want.
  You can giving an explicit name to the model by using:
  model = named_model(list, "Foo")
    warnings.warn(

and the only way to avoid the warning I could find is this adjusted version:

import factory
from pytest_factoryboy import register, named_model


class User:
    def __init__(self, flags):
        self.flags = flags


class NamedList(factory.ListFactory):
    class Meta:
        model = named_model(list, "NamedList")


@register
class UserFactory(factory.Factory):
    class Meta:
        model = User

    flags = factory.List(["a", "b", "c"], list_factory=NamedList)


def test_example(user_factory):
    user = user_factory.build()
    assert user.flags == ["a", "b", "c"]

Do I miss something obvious or is the list_factory + NamedList boilerplate required to avoid the warning?

pytest-factoryboy 2.5.0

[youtux]

I think this is a bug in pytest-factoryboy generation of related fixtures for factory.List.

I’ll check this in the next few weeks.

[youtux]

@nblock I spent some time investigating this, and I agree with @skarzi; I can’t think of an elegant way of fixing this, and your solution seems indeed correct and clear.