A FuzzyAttribute for factory_boy to choose a random foreign key instance of a model.

fuzzy_foreign_key.py

class FuzzyForeignKeyChoice(factory.fuzzy.BaseFuzzyAttribute):
    """
    A custom FuzzyAttribute for ``factory_boy`` which choses a random instance
    of a model for a new instance's field value.
    """
    def __init__(self, model):
        self.model = model

    def get_queryset(self):
        """
        Return a query set of instances of the given model.

        By default returns a queryset representing all instances.
        """
        return self.model.objects.all()

    def fuzz(self):
        # At the moment of fuzzying the field, obtain a query set of the
        # given model and return a random value
        return random.choice(list(self.get_queryset()))

A perhaps simpler way to generate a random FK with FactoryBoy, without the need for this class:

foo = factory.LazyAttribute(lambda a: MyModel.objects.order_by('?').first())