I'm trying to test a many-to-many relationship between two Django models using factory_boy. The factory_boy documentation doesn't appear to discuss this and I'm having trouble figuring out what I'm doing wrong. When I run the first test, I get the error "AttributeError: 'Pizza' object has no attribute 'topping'". I get a similar error for the second test.
When I run the tests in the debugger, I can see a 'toppings' object but it don't understand how to get the name from it. Have I defined PizzaFactory's _prepare method properly? How do you access the name in one table from the other table when you have a many-to-many relationship?
Thanks.
from django.db import models
class Topping(models.Model):
name = models.CharField(max_length=50)
def __unicode__(self):
return self.name
class Pizza(models.Model):
name = models.CharField(max_length=100)
toppings = models.ManyToManyField(Topping)
def __unicode__(self):
return self.name
import factory
from models import Topping, Pizza
class ToppingFactory(factory.Factory):
name = 'mushrooms'
class PizzaFactory(factory.Factory):
name = 'Vegetarian'
@classmethod
def _prepare(cls, create, **kwargs):
topping = ToppingFactory()
pizza = super(PizzaFactory, cls)._prepare(create, **kwargs)
pizza.toppings.add(topping)
return pizza
from django.test import TestCase
import factory
from app.models import Topping, Pizza
from app.factories import ToppingFactory, PizzaFactory
class FactoryTestCase(TestCase):
def test_pizza_has_mushrooms(self):
pizza = PizzaFactory()
self.assertTrue(pizza.topping.name, 'mushrooms')
def test_mushrooms_on_pizza(self):
topping = ToppingFactory()
self.assertTrue(topping.pizza.name, 'Vegetarian')
I believe you need to use the @factory.post_generation
decorator:
class PizzaFactory(factory.Factory):
name = 'Vegetarian'
@factory.post_generation
def toppings(self, create, extracted, **kwargs):
if not create:
# Simple build, do nothing.
return
if extracted:
# A list of groups were passed in, use them
for topping in extracted:
self.toppings.add(topping)
Then you would call it in tests.py pizza = PizzaFactory.create(toppings=(topping1, topping2, tooping3))
From https://factoryboy.readthedocs.org/en/latest/recipes.html.
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