Setting Up RSpec and FactoryGirl

Not another RSpec tutorial! I know, there’s plenty of well written tutorials out there. But, thankfully, this is only a cheat sheet. The article below outlines the steps to get RSpec and Factory girl set up in your Rails app. If you want a TL;DR, follow the code snippets and skip all the text.

First of all we need to add rspec-rails and factory_girl_rails to the Gemfile.

group :development, :test do
  gem 'rspec-rails', '~> 3.5'
  gem 'factory_girl_rails'
end

Next run:

$ bundle install
$ rails generate rspec:install

This will generate a spec/ folder inside your application. You can remove the test/ folder if it exists.

Next create the file spec/support/factory_girl.rb and paste in:

# spec/support/factory_girl.rb
RSpec.configure do |config|
  config.include FactoryGirl::Syntax::Methods
end

This makes method calls less verbose. For example instead of FactoryGirl.build you can now use build.

Next, uncomment the following line in spec/rails_helper.rb to autoload files in the support/ directory.

Dir[Rails.root.join('spec/support/**/*.rb')].each { |f| require f }

Everything is now setup. The next step is to generate a test and create a factory. Then we need to make sure everything passes.

Generating a test and running it

An RSpec test will be generated whenever you generate a model or controller. RSpec also offers generators to generate a test only. For example here’s how to generate a test for the model, Widget.

rails generate rspec:model widget

Check the RSpec documentation on generators to learn more.

Fun fact: with Factory Girl installed, a factory will also be generated when you generate a test.

Here are the files created when running the above RSpec generator. This should also generate a Factory Girl file spec/factories/widgets.rb.

# spec/models/widget_spec.rb
require 'rails_helper'
RSpec.describe Widget, type: :model do
  pending "add some examples to (or delete) #{__FILE__}"
end

# spec/factories/widgets.rb
FactoryGirl.define do
  factory :widget do
  end
end

To run the test:

bundle exec rspec spec

✅ RSpec + Factory Girl installation