====== Factory Boy ======
===== Introduction =====
==== What is Factory Boy? ====

Factory Boy aim is to replace static and hard to maintain complex object fixtures (test data).

This is test data created with factory boy (We need a 200€, paid order, shipping to australia, for a VIP customer):
<code python>
def test_with_factory_boy(self):
	order = OrderFactory(
		amount=200,
		status='PAID',
		customer__is_vip=True,
		address__country='AU',
	)

</code>
This is data created without factory boy:
<code python>
def test_without_factory_boy(self):
	address = Address(
		street="42 fubar street",
		zipcode="42Z42",
		city="Sydney",
		country="AU",
	)
	customer = Customer(
		first_name="John",
		last_name="Doe",
		phone="+1234",
		email="john.doe@example.org",
		active=True,
		is_vip=True,
		address=address,
	)
</code>

==== Installation ====
<code>
$ pip install factory_boy
</code>
==== ORMs ====
=== MongoEngine ===
<code python>
from factory.mongoengine import MongoEngineFactory
# ...
class User(Document):
# ...
class UserFactory(MongoEngineFactory):
</code>
===== First steps =====
==== Factories ====
Factories declare a set of attributes for an object. The class of this object must be defined in the ''model'' attribute of a subclass ''Meta'' (:!: In previous versions the class ''Meta'' with its attribute ''model'' it is substituted by ''FACTORY_FOR'' attribute):
<code python>
import factory
import models

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

    first_name = 'John'
    last_name = 'Doe'
    admin = False
</code>

From here we can:
<code python>
# Build a not saved user
user = UserFactory.build()
# Build a saved user
user = UserFactory.create()
# Build a saved user
user = UserFactory()
# Returns a dict of attributes that can be used to build a user
attributes = UserFactory.attributes()
# Build a not saved user overriding its first_name
user = UserFactory.build(first_name='Joe')
# Build ten not saved users named Joe
users = USerFactory.build(10, first_name="Joe")
</code>

=== Derived values ===
We can create a field which is derived from others (this example will put ''joe.blow@example.com'' in email field):
<code python>
class UserFactory(factory.Factory):
    FACTORY_FOR = models.User
    first_name = 'Joe'
    last_name = 'Blow'
    email = factory.LazyAttribute(lambda a: '{0}.{1}@example.com'.format(a.first_name, a.last_name).lower())
</code>

=== Unique values in sequence ===
We can create a field which is auto-incremented as:
<code python>
class UserFactory(factory.Factory):
    FACTORY_FOR = models.User
    email = factory.Sequence(lambda n: 'person{0}@example.com'.format(n))
</code>

=== Associate factories ===
We can associate a field with other factory to create other sub instance:
<code python>
class PostFactory(factory.Factory):
    FACTORY_FOR = models.Post
    author = factory.SubFactory(UserFactory)
</code>