Test your app with RSpec

Created by Clemens Helm, @clemenshelm and Floor Drees, @floordrees

Updated by Ana Schwendler, @anaschwendler

This guide assumes that you have already built a Rails Girls app by following the app development guide.

RSpec is a Ruby testing framework, that describes our application’s behavior in a syntax that doesn’t look much like Ruby. It outputs test results in your terminal, so you’ll test your reading skills as well (pun intended).

COACH: Talk about testing and Behavior-Driven Development.

1. Add RSpec gem

Open up your Gemfile and add this line to the :development and :test groups, above the end tag:

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

and run

bundle install

to install the gem.

Next create the spec/ directory inside your application:

mkdir spec/

The spec/ directory is where your tests will reside. Finally run the following command:

rails generate rspec:install

This adds the following files which are used for configuration:

• .rspec
• spec/spec_helper.rb
• spec/rails_helper.rb

2. Create your first test!

Rubyists often use the words ‘test’ and ‘specification’ interchangeably, that’s why you’ll store your tests in the ‘specs’ folder. To do that, do the following steps:

We will be creating a test for ou idea model, to do that in the elegant way in Rails:

• Create a models folder in your spec folder, by running in the terminal:

mkdir spec/models

• Save your test as idea_spec.rb (<model_name>_spec.rb).

Inside that new file, in our first test we will want to guarantee that an idea has a name. In order to do that let’s describe one of our specifications:

require "rails_helper"

RSpec.describe Idea, type: :model do
  it "has a name" do
    skip
  end
end

In your terminal run

rspec spec/models/idea_spec.rb

which will output that your test is pending as it’s not yet implemented.

COACH: Talk about googling terminal output.

Let’s do something about that!

require "rails_helper"

RSpec.describe Idea, type: :model do
  it "has a name" do # yep, you can totally use 'it'
    idea = Idea.create!(name: "My Awesome Idea Name") # creating a new idea 'instance'
    expect(idea.name).to eq("My Awesome Idea Name") # this is our expectation
  end
end

should give you a more satisfying output.

3. Refactoring

You could actually also create two ideas, to be sure that our project is creating ideas in the right way:

require "rails_helper"

RSpec.describe Idea, type: :model do
  it "has a name" do # yep, you can totally use 'it'
    idea = Idea.create!(name: "My Awesome Idea Name") # creating a new idea 'instance'
    second_idea = Idea.create!(name: "My Second Idea Name") # creating another new idea 'instance'
    expect(second_idea.name).to eq("My Second Idea Name") # this is our expectation
  end
end

which test more things.

COACH: Talk a bit about refactoring.

4. Marking to-do’s with tests

Yeah! To-do lists. Awesome. A nifty RSpec feature is the functionality to mark certain tests as pending. In other words, your first thinking about what the implementation should accomplish then write in a test to verify if it is working.

Let’s create our next test, by adding the lines below to our idea_spec.rb

it "has a description"

will mark a test as pending.

Can you finish this test? Can you think about other tests?

5. Behavior-Driven Development

COACH: Talk a bit about Behavior-Driven Development.

By now you can create more tests alone. Feel free to talk to your coach to do that, or ways to create more tests.

Happy testing!