Speed up rspec tests - part1

Kamil Baćkowski

Example feature spec

describe 'Lists', type: :feature, js: true do
  before do
    # time consuming setup which takes about 6s
  end

  # each it takes about 1 second
  it 'should be able to browse lists' do
  end

  it 'should be able to edit a list' do
  end

  it 'should be able to add companies to list' do
  end

  it 'should be able to remove companies from list' do
  end

  it 'should be able to delete a list' do
  end
end

How long it takes ?

rspec spec/features/lists_spec.rb

.....

Finished in 35.34 seconds (files took 9.99 seconds to load)
5 examples, 0 failures

How to speed up ?

We can combine all tests cases into one so that before hook will execute only once.

describe 'Lists', type: :feature, js: true do
  before do
    # time consuming setup which takes about 6s
  end

  it "should be able to manage lists" do
    #should be able to edit a list
    ...
    #should be able to add companies to list
    ...
    #should be able to remove companies from list
    ...
    #should be able to delete a list
    ...
  end
end

We can do it better!

Use aggregate_failures from rspec

require 'spec_helper'

describe 'Lists', type: :feature, js: true do
  before do
    # time consuming setup which takes about 6s
  end

  it 'should be able to manage lists' do
    aggregate_failures 'should be able to browse lists' do
    end

    aggregate_failures 'should be able to edit a list' do
    end

    aggregate_failures 'should be able to add companies to list' do
    end

    aggregate_failures 'should be able to remove companies from list' do
    end

    aggregate_failures 'should be able to delete a list' do
    end
  end
end

How long it takes ?

rspec spec/features/lists_spec.rb

.

Finished in 11.23 seconds (files took 9.99 seconds to load)
1 example, 0 failures

Pros & Cons

• Tests runs 3x times faster
• Tests becomes dependant on each other

What happens when some test fails ?

• By default all next aggregate_failures within block will not execute
• We can change this by adding aggregate_failures metadata and then all aggregate_failures will be executed and rspec will report all errors.

What about controllers ?

describe CompanyOfficesController, type: :controller do
  describe '#create' do
    it 'validates params' do
      sign_in user
      post :create, name: ''
      expect(response).to render_template('new')
      expect(flash[:error]).not_to be_nil
    end

    it 'creates record when params are valid' do
      sign_in user
      expect do
        post :create, name: 'My office'
      end.to change(CompanyOffice, :count).by 1
    end

    it 'creates record when params are valid and redirect to index' do
      sign_in user
      post :create, name: 'My office'
      expect(response).to redirect_to(company_offices_path)
    end
  end
end

Using aggregate_failures

describe CompanyOfficesController, type: :controller do
  describe '#create' do
    it 'creates office' do
      sign_in user

      aggregate_failures 'validates params' do
        post :create, name: ''
        expect(response).to render_template('new')
        expect(flash[:error]).not_to be_nil
      end

      aggregate_failures 'creates record when params are valid and redirect' do
        expect do
          post :create, name: 'My office'
        end.to change(CompanyOffice, :count).by 1
        expect(response).to redirect_to(company_offices_path)
      end
    end
  end
end

Summary

I encourage to use this for all features specs and some controller specs which uses the same setup.

Questions ?