How to set dynamic many to many in factory boy with through table?

Question

I'm having problems setting up a many to many relationship with a set of django models in factory boy, using a through relationship. I have a bunch of recipes and ingredients. There is a many-to-many relation between Recipes and Ingredients through a model that sets a quantity. I have factories for each model but cannot get them to link up.

simplified models.py:

class Ingredient(models.Model):
    name = models.CharField(max_length=40)

class Recipe(models.Model):
    name = models.CharField(max_length=128)
    ingredients = models.ManyToManyField(Ingredient, through='RecipeIngredient')

class RecipeIngredient(models.Model):
    recipe = models.ForeignKey(Recipe)
    ingredient = models.ForeignKey(Ingredient)
    quantity = models.IntegerField(default=1)

simplified factories.py

class RecipeFactory(factory.django.DjangoModelFactory):
    class Meta:
        model = Recipe

class IngredientFactory(factory.django.DjangoModelFactory):
    class Meta:
        model = Ingredient

class RecipeIngredientFactory(factory.django.DjangoModelFactory):
    class Meta:
        model = RecipeIngredient
    recipe = factory.SubFactory(RecipeFactory)
    ingredient = factory.SubFactory(IngredientFactory)
    quantity = 1

I've tried messing with factory.RelatedFactory but haven't really got anywhere. Ideally I just want to be able to do the following:

recipe = RecipeFactory(name="recipe1")
ingredient = IngredientFactory(name="ingredient1")
ri = RecipeIngredientFactory(recipe=recipe, ingredient=ingredient)

Doing this though does not set the many to many relation on either side, and also seems to fail to create the recipeingredient model itself. Does anyone know of a way to do this?

Edit:

I've also tried:

class RecipeWith3Ingredients(RecipeFactory):
    ingredient1 = factory.RelatedFactory(RecipeIngredientFactory, 'recipe')
    ingredient2 = factory.RelatedFactory(RecipeIngredientFactory, 'recipe')
    ingredient3 = factory.RelatedFactory(RecipeIngredientFactory, 'recipe')

But cant get my head around how I'd create these objects with a pre-existing recipe and set of ingredients.

Answer 1

I've just recreated this setup and I'm struggling to see what the problem is. Here are several tests that demonstrate that all seems to be working well? Or am I misunderstanding the question?

# create recipe ingredient and recipe ingredient
recipe = RecipeFactory(name="recipe1")
ingredient = IngredientFactory(name="ingredient1")
recipe_ingredient = RecipeIngredientFactory(recipe=recipe, ingredient=ingredient)

# recipe created?       
r = Recipe.objects.all().first()
self.assertEqual(r, recipe)

# ingredient created?
i = Ingredient.objects.all().first()
self.assertEqual(i, ingredient)

# recipe ingredient created?
ri = RecipeIngredient.objects.all().first()
self.assertEqual(ri, recipe_ingredient)        

# test many to many
self.assertEqual(ri, r.recipeingredient_set.all()[0])
self.assertEqual(ri, i.recipeingredient_set.all()[0])

# add a new ingredient to recipe 1
ingredient2 = IngredientFactory(name='ingredient2')
recipe_ingredient2 = RecipeIngredientFactory(recipe=recipe, ingredient=ingredient2)

# test many to many
self.assertTrue(recipe_ingredient in r.recipeingredient_set.all())
self.assertTrue(recipe_ingredient2 in r.recipeingredient_set.all())

# create a pre-existing recipe and a set of ingredients
pizza_recipe = RecipeFactory(name='Pizza')
cheese_on_toast_recipe = RecipeFactory(name='Cheese on toast')

cheese_ingredient = IngredientFactory(name='Cheese')
tomato_ingredient = IngredientFactory(name='Tomato')
pizza_base_ingredient = IngredientFactory(name='Pizza base')
toast_ingredient = IngredientFactory(name='Toast')

# now put together
RecipeIngredientFactory(recipe=pizza_recipe, ingredient=cheese_ingredient)
RecipeIngredientFactory(recipe=pizza_recipe, ingredient=tomato_ingredient)
RecipeIngredientFactory(recipe=pizza_recipe, ingredient=pizza_base_ingredient)

RecipeIngredientFactory(recipe=cheese_on_toast_recipe, ingredient=cheese_ingredient)        
RecipeIngredientFactory(recipe=cheese_on_toast_recipe, ingredient=toast_ingredient)        

# test pizza recipe
pizza_ingredients = [cheese_ingredient, tomato_ingredient, pizza_base_ingredient]
pr = Recipe.objects.get(name='Pizza')

for recipe_ingredient in pr.recipeingredient_set.all():
    self.assertTrue(recipe_ingredient.ingredient in pizza_ingredients)

# test cheese on toast recipe
cheese_on_toast_ingredients = [cheese_ingredient, toast_ingredient]
cotr = Recipe.objects.get(name='Cheese on toast')

for recipe_ingredient in cotr.recipeingredient_set.all():
    self.assertTrue(recipe_ingredient.ingredient in cheese_on_toast_ingredients)

# test from ingredients side
cheese_recipes = [pizza_recipe, cheese_on_toast_recipe]
ci = Ingredient.objects.get(name='Cheese')

for recipe_ingredient in ci.recipeingredient_set.all():
    self.assertTrue(recipe_ingredient.recipe in cheese_recipes)