RSpec cheatsheet

RSpec_cheatsheet.md

RSpec Cheatsheet

Specs layers

 +-----------------------------------------------------------------------------------------+

   +----------+                                                       +------------------+
   |          |                                                       |                  |
   |  View    |                                                       |                  |
   |  Specs   |            View                                       |                  |
   |          |                                                       |                  |
   +----------+                                                       |                  |
                                                                      |                  |
 +--------------------------------------------------------------------+                  +-+
                                                                      |                  |
                                                                      |                  |
                           Route                                      |                  |
                                                                      |                  |
                                                                      |                  |
+---------------------------------------------------------------------+                  +-+
                                                                      |                  |
  +-------------+                                                     |                  |
  |             |                                                     |                  |
  |    Helper   |                                                     |     Features     |
  |    Specs    |          Helper       +-------------------+         |     Specs        |
  |             |                       |                   |         |                  |
  +-------------+                       |                   |         |                  |
                                        |                   |         |                  |
+---------------------------------------+                   +---------+                  +-+
                                        |                   |         |                  |
                                        |                   |         |                  |
                           Controller   |   Controller      |         |                  |
                                        |   Specs           |         |                  |
                                        |                   |         |                  |
                                        |                   |         |                  |
+---------------------------------------+                   +---------+                  +-+
                                        |                   |         |                  |
  +------------+                        |                   |         |                  |
  |            |                        +-------------------+         |                  |
  |    Model   |            Model                                     |                  |
  |    Specs   |                                                      |                  |
  |            |                                                      |                  |
  +------------+                                                      +------------------+

+-------------------------------------------------------------------------------------------+

Model Specs

example:

#spec/models/car_spec.rb
RSpec.describe Car, '#available?' do
  it 'returns true if it's available' do
    car = build(:car, available: true)
    
    expect(car.available?).to eq true
  end
end

View specs

Documentation: Relishapp view-specs

Note: With devise, do not forget to add following lines on your rails_helper.rb

config.include Devise::TestHelpers, type: :controller
config.include Devise::TestHelpers, type: :view

Features

assign: used to assign an instance variable which can be called in a view.
example: my view uses @cars variable

assign(:cars, [
  Car.create!(:name => "Civic"),
  Car.create!(:name => "Clio")
])

render: try to render view related to assign variable example:

RSpec.describe "widgets/index" do

  context "with 2 widgets" do
    before(:each) do
      assign(:cars, [
        Car.create!(:name => "Civic"),
        Car.create!(:name => "Clio")
      ])
    end

    it "displays both cars" do
      render

      expect(rendered).to match /Civic/
      expect(rendered).to match /Clio/
    end
  end
end

You can also render a specifi template:

render template: 'cars/car.html.erb'

You can also render a partial template:

render partial: 'cars/car.html.erb', locals: {car: car}

How to stub a helper

require 'rails_helper'

RSpec.describe 'secrets/index' do
  before do
    allow(view).to receive(:admin?).and_return(true)
  end

  it 'checks for admin access' do
    render
    expect(rendered).to match /Secret admin area/
  end
end

example:

# spec/views/car/_car.html.erb_spec.rb
require 'rails_helper'

RSpec.describe 'car/_car.html.erb' do
  context 'if it has an image' do
    it 'renders the image inline' do
      car = build(:car, image_url: 'http://example.com/car.jpg')
      
      render partial: 'car/car.html.erb', locals: { car: car }
      
      expect(rendered).to have_selector "img[src='#{car.image_url}]"
    end
  end
end

Same example with a user session:

# spec/views/car/_car.html.erb_spec.rb
require 'rails_helper'

RSpec.describe 'car/_car.html.erb' do
  context 'if it has an image' do
    it 'renders the image inline' do
      current_user = double('user')
      allow(current_user).to receive(:cache_can_create?).and_return(true)
      allow(view).to receive(:current_user).and_return(current_user)
      car = build(:car, image_url: 'http://example.com/car.jpg')
      
      render partial: 'car/car.html.erb', locals: { car: car }
      
      expect(rendered).to have_selector "img[src='#{car.image_url}]"
    end
  end
end

Controller Specs

documentation: https://www.relishapp.com/rspec/rspec-rails/docs/controller-specs

Rails specific mathers

render_template
expect(response).to render_template(:new)

redirect_to
expect(response).to redirect_to(location)

have_http_status
expect(response).to have_http_status(:created)

example:

require 'rails_helper'

RSpec.describe CarsController, '#create' do
  context 'When the program is invalid' do
    it 're-renders the form' do
      post :create, car: attributes_for(:car, :invalid)

      expect(response).to render_template(:new)
    end
  end
end

Same example with a user session:

require 'rails_helper'

RSpec.describe CarsController, '#create' do
  context 'When the program is invalid' do
    it 're-renders the form' do
      user = double('user')
      allow(user).to receive(:can_create?).and_return(true)
      allow(request.env['warden']).to receive(:authenticate!).and_return(user)
      allow(controller).to receive(:current_user).and_return(user)
      
      post :create, car: attributes_for(:car, :invalid)

      expect(response).to render_template(:new)
    end
  end
end

Note:

• All the allow instructions have been used to stub devise authentication
• attributes_for is a FactoryGirl method that returns a hash of attributes that can be used to build a Car instance

Features Specs

....