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Extract examples out to a different file so that the readme people se…
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…e on Github won't contact examples from master
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jferris committed Feb 7, 2011
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lib/**/*.rb
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GETTING_STARTED.md
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Getting Started
===============

Defining factories
------------------

Each factory has a name and a set of attributes. The name is used to guess the class of the object by default, but it's possible to explicitly specify it:

# This will guess the User class
FactoryGirl.define do
factory :user do
first_name 'John'
last_name 'Doe'
admin false
end

# This will use the User class (Admin would have been guessed)
factory :admin, :class => User do
first_name 'Admin'
last_name 'User'
admin true
end

# The same, but using a string instead of class constant
factory :admin, :class => 'user' do
first_name 'Admin'
last_name 'User'
admin true
end
end

It is highly recommended that you have one factory for each class that provides the simplest set of attributes necessary to create an instance of that class. If you're creating ActiveRecord objects, that means that you should only provide attributes that are required through validations and that do not have defaults. Other factories can be created through inheritance to cover common scenarios for each class.

Attempting to define multiple factories with the same name will raise an error.

Factories can be defined anywhere, but will be automatically loaded if they
are defined in files at the following locations:

test/factories.rb
spec/factories.rb
test/factories/*.rb
spec/factories/*.rb

Using factories
---------------

factory_girl supports several different build strategies: build, create, attributes_for and stub:

# Returns a User instance that's not saved
user = FactoryGirl.build(:user)

# Returns a saved User instance
user = FactoryGirl.create(:user)

# Returns a hash of attributes that can be used to build a User instance:
attrs = FactoryGirl.attributes_for(:user)

# Returns an object with all defined attributes stubbed out:
stub = FactoryGirl.stub(:user)

No matter which strategy is used, it's possible to override the defined attributes by passing a hash:

# Build a User instance and override the first_name property
user = FactoryGirl.build(:user, :first_name => 'Joe')
user.first_name
# => "Joe"

If repeating "FactoryGirl" is too verbose for you, you can mix the syntax methods in:

# rspec
RSpec.configure do |config|
config.include Factory::Syntax::Methods
end

# Test::Unit
class Test::Unit::TestCase
include Factory::Syntax::Methods
end

Lazy Attributes
---------------

Most factory attributes can be added using static values that are evaluated when the factory is defined, but some attributes (such as associations and other attributes that must be dynamically generated) will need values assigned each time an instance is generated. These "lazy" attributes can be added by passing a block instead of a parameter:

factory :user do
# ...
activation_code { User.generate_activation_code }
end

Dependent Attributes
--------------------

Attributes can be based on the values of other attributes using the proxy that is yielded to lazy attribute blocks:

factory :user do
first_name 'Joe'
last_name 'Blow'
email { "#{first_name}.#{last_name}@example.com".downcase }
end

FactoryGirl.create(:user, :last_name => 'Doe').email
# => "joe.doe@example.com"

Associations
------------

Associated instances can be generated by using the association method when
defining a lazy attribute:

factory :post do
# ...
author
end

You can also specify a different factory or override attributes:

factory :post do
# ...
association :author, :factory => :user, :last_name => 'Writely'
end

The behavior of the association method varies depending on the build strategy used for the parent object.

# Builds and saves a User and a Post
post = FactoryGirl.create(:post)
post.new_record? # => false
post.author.new_record # => false

# Builds and saves a User, and then builds but does not save a Post
post = FactoryGirl.build(:post)
post.new_record? # => true
post.author.new_record # => false

If the factory name is the same as the association name, the factory name can
be left out.

Inheritance
-----------

You can easily create multiple factories for the same class without repeating common attributes by using inheritance:

factory :post do
# the 'title' attribute is required for all posts
title 'A title'
end

factory :approved_post, :parent => :post do
approved true
# the 'approver' association is required for an approved post
association :approver, :factory => :user
end

Sequences
---------

Unique values in a specific format (for example, e-mail addresses) can be
generated using sequences. Sequences are defined by calling sequence in a
definition block, and values in a sequence are generated by calling
Factory.next:

# Defines a new sequence
FactoryGirl.define do
sequence :email do |n|
"person#{n}@example.com"
end
end

Factory.next :email
# => "person1@example.com"

Factory.next :email
# => "person2@example.com"

Sequences can be used as attributes:

factory :user do
email
end

Or in lazy attributes:

factory :invite do
invitee { Factory.next(:email) }
end

And it's also possible to define an in-line sequence that is only used in
a particular factory:

factory :user do
sequence(:email) {|n| "person#{n}@example.com" }
end

Callbacks
---------

Factory_girl makes available three callbacks for injecting some code:

* after_build - called after a factory is built (via FactoryGirl.build)
* after_create - called after a factory is saved (via FactoryGirl.create)
* after_stub - called after a factory is stubbed (via FactoryGirl.stub)

Examples:

# Define a factory that calls the generate_hashed_password method after it is built
factory :user do
after_build { |user| generate_hashed_password(user) }
end

Note that you'll have an instance of the user in the block. This can be useful.

You can also define multiple types of callbacks on the same factory:

factory :user do
after_build { |user| do_something_to(user) }
after_create { |user| do_something_else_to(user) }
end

Factories can also define any number of the same kind of callback. These callbacks will be executed in the order they are specified:

factory :user do
after_create { this_runs_first }
after_create { then_this }
end

Calling FactoryGirl.create will invoke both after_build and after_create callbacks.

Also, like standard attributes, child factories will inherit (and can also define) callbacks from their parent factory.

Alternate Syntaxes
------------------

Users' tastes for syntax vary dramatically, but most users are looking for a common feature set. Because of this factory_girl supports "syntax layers" which provide alternate interfaces. See Factory::Syntax for information about the various layers available. For example, the Machinist-style syntax is popular:

require 'factory_girl/syntax/blueprint'
require 'factory_girl/syntax/make'
require 'factory_girl/syntax/sham'

Sham.email {|n| "#{n}@example.com" }

User.blueprint do
name { 'Billy Bob' }
email { Sham.email }
end

User.make(:name => 'Johnny')

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