Factoring In Nests

October 30, 2013

I am building an application that uses several nested attributes: Users have many Goals (Goals belongto Users), and Goals have many Hours (Hours belongto Goals).

Using FactoryGirl to create a User is straightforward:

FactoryGirl.define do
  factory :user do
    sequence :name  { |n| "person#{n}" }
    sequence :email { |n| "person#{n}@example.com" }
  end
end

describe User do
  before  { @user = FactoryGirl.create(:user) }
  subject { @user }
  it { should respond_to(:name) }
  ...
end

How do I create Goals that are linked to the User?

How to create Factories for nested attributes

1. Make a new Factory for producing Goals:

FactoryGirl.define do
  factory :goal do
    sequence :description { |n| "my goal #{n}" }
    sequence :motivation  { |n| "my motivation #{n}" }
  end
end

2. Call the Goal Factory from the User Factory and store the Goals in an Array

FactoryGirl.define do
  factory :user do
    sequence :name { |n| "person#{n}" }
    sequence :email { |n| "person#{n}@example.com" }

    goals { Array.new(1) { FactoryGirl.build(:goal) } }

  end
end

Your objects will look like this:

> p @user
#<User id: 1, name: "person1", email: "person1@example.com", ... >
> p @user.goals.first
#<ActiveRecord::Associations::CollectionProxy [#<Goal id: 1, user_id: 1, description: "my goal 1", motivation: "my motivation 1", ...]>

Create Hours for Goals in the same manner: create a Factory for making Hours, call the Hours Factory from the Goals Factory.

FactoryGirl.define do
  factory :hour do
    duration { 100 * rand(36) }
    ...
  end
end

FactoryGirl.define do
  factory :goal do
    sequence :description { |n| "my goal #{n}" }
    sequence :motivation  { |n| "my motivation #{n}" }

    hours { Array.new(3) { FactoryGirl.build(:hour) } }
  end
end

Checking your objects:

> p @user
#<User id: 1, name: "person1", email: "person1@example.com", ... >
> p @user.goals.first
#<ActiveRecord::Associations::CollectionProxy [#<Goal id: 1, user_id: 1, description: "my goal 1", motivation: "my motivation 1", ...]>
> p @user.goals.first.hours.first
#<ActiveRecord::Associations::CollectionProxy [#<Hour id: 1, goal_id: 1, duration: 3200 , ...]>

Awesome.