factory_girl 使用帮助

Getting Started
Update Your Gemfile
If you're using Rails, you'll need to change the required version of factory_girl_rails:

gem "factory_girl_rails", "~> 3.0"
If you're not using Rails, you'll just have to change the required version of factory_girl:

gem "factory_girl", "~> 3.0"
Once your Gemfile is updated, you'll want to update your bundle.

Using Without Bundler
If you're not using Bundler, be sure to have the gem installed and call:

require 'factory_girl'
Once required, assuming you have a directory structure of spec/factories or test/factories, all you'll need to do is run

FactoryGirl.find_definitions
If you're using a separate directory structure for your factories, you can change the definition file paths before trying to find definitions:

FactoryGirl.definition_file_paths = %w(custom_factories_directory)
FactoryGirl.find_definitions
If you don't have a separate directory of factories and would like to define them inline, that's possible as well:

require 'factory_girl'

FactoryGirl.define do
  factory :user do
    name 'John Doe'
    date_of_birth { 21.years.ago }
  end
end
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
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.build_stubbed(:user)

# Passing a block to any of the methods above will yield the return object
FactoryGirl.create(:user) do |user|
  user.posts.create(attributes_for(:post))
end
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 FactoryGirl::Syntax::Methods
end

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

# Cucumber
World(FactoryGirl::Syntax::Methods)
This would allow you to write:

describe User, "#full_name" do
  subject { create(:user, first_name: "John", last_name: "Doe") }

  its(:full_name) { should == "John Doe" }
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 }
  date_of_birth   { 21.years.ago }
end
In addition to running other methods dynamically, you can use FactoryGirl's syntax methods (like build, create, and generate) within dynamic attributes without having to prefix the call with FactoryGirl.. This allows you to do:

sequence(:random_string) {|n| LoremIpsum.generate }

factory :post do
  title { generate(:random_string) } # instead of FactoryGirl.generate(:random_string)
end

factory :comment do
  post
  body { generate(:random_string) }  # instead of FactoryGirl.generate(:random_string)
end
Aliases
Aliases allow you to use named associations more easily.

factory :user, aliases: [:author, :commenter] do
  first_name    "John"
  last_name     "Doe"
  date_of_birth { 18.years.ago }
end

factory :post do
  author
  # instead of
  # association :author, factory: :user
  title "How to read a book effectively"
  body  "There are five steps involved."
end

factory :comment do
  commenter
  # instead of
  # association :commenter, factory: :user
  body "Great article!"
end
Dependent Attributes
Attributes can be based on the values of other attributes using the evaluator 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
# => "[email protected]"
Transient Attributes
There may be times where your code can be DRYed up by passing in transient attributes to factories.

factory :user do
  ignore do
    rockstar true
    upcased  false
  end

  name  { "John Doe#{" - Rockstar" if rockstar}" }
  email { "#{name.downcase}@example.com" }

  after(:create) do |user, evaluator|
    user.name.upcase! if evaluator.upcased
  end
end

FactoryGirl.create(:user, upcased: true).name
#=> "JOHN DOE - ROCKSTAR"
Static and dynamic attributes can be ignored. Ignored attributes will be ignored within attributes_for and won't be set on the model, even if the attribute exists or you attempt to override it.

Within FactoryGirl's dynamic attributes, you can access ignored attributes as you would expect. If you need to access the evaluator in a FactoryGirl callback, you'll need to declare a second block argument (for the evaluator) and access ignored attributes from there.


more： https://github.com/thoughtbot/factory_girl/blob/master/GETTING_STARTED.md