[SOLVED] Avoiding duplicates with factory

Avoiding duplicates with factory_boy factories

I'm using factory_boy to create test fixtures. I've got two simple factories, backed by SQLAlchemy models (simplified below).

I'd like to be able to call AddressFactory.create() multiple times, and have it create a Country if it doesn't already exist, otherwise I want it to re-use the existing record.

class CountryFactory(factory.Factory):
    FACTORY_FOR = Country

    cc = "US"
    name = "United States"


class AddressFactory(factory.Factory):
    FACTORY_FOR = Address

    name = "Joe User"
    city = "Seven Mile Beach"
    country = factory.SubFactory(CountryFactory, cc="KY", name="Cayman Islands")

My question is: how can I set up these factories so that factory_boy doesn't try to create a new Country every time it creates an Address?

Solution

Since version 3.0.0, SQLAlchemy factories support the sqlalchemy_get_or_create option. As the documentation says, "Fields whose name are passed in this list will be used to perform a Model.query.one_or_none() or the usual Session.add()".

Using the example from the docs:

class UserFactory(factory.alchemy.SQLAlchemyModelFactory):
    class Meta:
        model = User
        sqlalchemy_session = session
        sqlalchemy_get_or_create = ('username',)

    username = 'john'

>>> User.query.all()
[]
>>> UserFactory()                   # Creates a new user
<User: john>
>>> User.query.all()
[<User: john>]

>>> UserFactory()                   # Fetches the existing user
<User: john>
>>> User.query.all()                # No new user!
[<User: john>]

>>> UserFactory(username='jack')    # Creates another user
<User: jack>
>>> User.query.all()
[<User: john>, <User: jack>]

Take into consideration that when sqlalchemy_get_or_create is used, any new values passed to the factory are NOT used to update an existing model.