Rails Girls Guides

Test your app with RSpec

Originally created by Clemens Helm, @clemenshelm and Floor Drees, @floordrees. Updated by Ana Schwendler, @anaschwendler

This guide is a part of the Rails Girls workshop main guides. Make sure you follow the numbered guides in order before continuing.

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).

Help from the coach

Talk about testing and Behavior-Driven Development.

1. Add the 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"
end

and run the following command to install the Ruby gem.

bundle install

Then run the following command, in order to setup RSpec in your app:

rails generate rspec:install

This adds the following files which are used for configuration:

2. Create your first test!

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

We will be creating a test for our Idea model. Create a models directory in your spec directory. Then create a new file called idea_spec.rb (<model_name>_spec.rb) in that directory.

Inside the new test file, we will want to make sure our idea has a name. In order to do that let’s describe one of our specifications:

require "rails_helper"

RSpec.describe Idea do
  it "has a name" do
    skip
  end
end

In the Terminal app run:

rspec spec/models/idea_spec.rb

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

Let’s add something to our test to make sure the idea has a name!

require "rails_helper"

RSpec.describe Idea 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

Run RSpec again, and you should see more satisfying green output this time, meaning all tests passed.

rspec spec/models/idea_spec.rb

3. Make to-do’s with tests

Yeah! Let’s create to-do lists. Awesome!

A nifty RSpec feature is the functionality to mark certain tests as pending like we saw before. In other words, first you think about what your models should do, before writing the implementation and the test. You have an idea of what your model should do beforehand, and then you can write the code and tests for it.

Let’s create our next test, by adding the lines below to our idea_spec.rb it will add another test and mark it as pending.

it "has a description"

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

Consult the RSpec documentation, or search for an RSpec tutorial online, to find out what kind of tests you can make.

4. Add more tests

We have our first test, we test if our idea has a name, but our idea can hold many more things. Let’s test if it has comments or not.

require "rails_helper"

RSpec.describe Idea do
  # Your other tests here...

  it "has comments" do
    idea = Idea.create!(name: "My Awesome Idea Name")
    comment = Comment.create!(
      user_name: "My name",
      body: "My helpful comment",
      idea: idea # Link the comment to the idea
    )

    expect(comment.idea).to eq(idea)
  end
end

5. Behavior-Driven Development

Help from the 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!

If you’re ever stuck during a guide, please ask your coach for help and also consult this handy cheatsheet for Ruby, Rails, the console, the Text Editor etc.

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