Installing FactoryGirl to Create Test Data in Rails

In this guide we are going to install a gem called FactoryGirl which will help us to streamline our code for test data creation.

Open the Gemfile, and include FactoryGirl in it.

# Gemfile

gem 'factory_girl_rails', '~> 4.7'

If you look at this code, we have grouped it into the development and test blocks. This will ensure it doesn't run in production. Now, type bundle in your console and this will take care of all dependencies.

Next, let's open the rails_helper.rb file and at the very bottom, and update it so it looks like this:

# spec/rails_helper.rb

ENV['RAILS_ENV'] ||= 'test'
require File.expand_path('../../config/environment', __FILE__)

abort("The Rails environment is running in production mode!") if Rails.env.production?
require 'spec_helper'
require 'rspec/rails'
require 'capybara/rails'

include Warden::Test::Helpers
Warden.test_mode!

ActiveRecord::Migration.maintain_test_schema!

RSpec.configure do |config|
  config.fixture_path = "#{::Rails.root}/spec/fixtures"
  config.use_transactional_fixtures = false
  config.before(:suite) { DatabaseCleaner.clean_with(:truncation) }
  config.before(:each) { DatabaseCleaner.strategy = :transaction }
  config.before(:each, :js => true) { DatabaseCleaner.strategy = :truncation }
  config.before(:each) { DatabaseCleaner.start }
  config.after(:each) { DatabaseCleaner.clean }
  config.infer_spec_type_from_file_location!
  config.filter_rails_from_backtrace!
  config.include FactoryGirl::Syntax::Methods # This is the line to add
end

Next, let's create a directory called factories with this terminal command (you can also manually create it in your text editor):

mkdir spec/factories

Inside this new directory, create specific factory files like this:

touch spec/factories/users.rb
touch spec/factories/posts.rb

The normal convention is to use the plural form of models to create factories. This means a User factory should be named users.rb.

Now open the posts.rb file that we just created. Name the first factory as post, and include all the fields from your schema file. We may need more than one factory for post, and this is why I've created two.

# spec/factories/posts.rb

FactoryGirl.define do
  factory :post do
    date Date.today
    rationale "Some Rationale"
    user
  end

  factory :second_post, class: "Post" do
    date Date.yesterday
    rationale "Some more content"
    user
  end
end

If you're unsure of any of these methods, especially the date methods such as Date.today, I recommend that you open the rails console and run them there to see what they equal.

Now let's check all of this in the console itself with the command:

rails c -e test

Here e stands for environment and we are letting the console know that we want to run this code in the test environment.

To test, let's create a post and second_post using FactoryGirl using the commands:

FactoryGirl.create(:post)
FactoryGirl.create(:second_post)

Next, we'll create a factory for users. The complete code is:

# spec/factories/users.rb

FactoryGirl.define do
  factory :user do
    first_name 'Jon'
    last_name 'Snow'
    email "test@test.com"
    password "asdfasdf"
    password_confirmation "asdfasdf"
  end

  factory :admin_user, class: "AdminUser" do
    first_name 'Admin'
    last_name 'User'
    email "admin@user.com"
    password "asdfasdf"
    password_confirmation "asdfasdf"
  end
end

Finally, let's create a user using FactoryGirl and the following command:

FactoryGirl.create(:user)

So, this is how you use FactoryGirl in rails.

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