Testing Rails with RSpec, Factory Bot, Faker and Shoulda Matchers

.rspec

--require spec_helper

edit.html.erb_spec.rb

# frozen_string_literal: true

# spec/views/posts/edit.html.erb_spec.rb

require 'rails_helper'

RSpec.describe 'posts/edit.html.erb', type: :view do 
  it 'renders ...' do
    # render
    # assert_select
    # expect(rendered).to match()
    skip '...'
  end
end

factory_bot.rb

# frozen_string_literal: true

# spec/support/factory_bot.rb

RSpec.configure do |config|
  config.include FactoryBot::Syntax::Methods
end

Gemfile

group :development, :test do
  gem 'factory_bot_rails'
  gem 'faker'
  gem 'rspec-rails'
  gem 'shoulda-matchers'
end

index.html.erb_spec.rb

# frozen_string_literal: true

# spec/views/posts/index.html.erb_spec.rb

require 'rails_helper'

RSpec.describe 'posts/index.html.erb', type: :view do
  before do
    assign :posts, create_list(:post, 3)
  end
  
  it 'renders a list of posts' do
    # render
    # assert_select
    skip '...'
  end
end

new.html.erb_spec.rb

# frozen_string_literal: true

# spec/views/posts/new.html.erb_spec.rb

require 'rails_helper'

RSpec.describe 'posts/new.html.erb', type: :view do 
  it 'renders ...' do
    # render
    # assert_select
    # expect(rendered).to match()
    skip '...'
  end
end

post_spec.rb

# frozen_string_literal: true

# spec/models/post_spec.rb

require 'rails_helper'

RSpec.describe Post, type: :model do
end

posts.rb

# frozen_string_literal: true

# spec/factories/posts.rb

FactoryBot.define do
  factory :post do
    title { Faker::Lorem.sentence }
    body { Faker::Lorem.paragraphs.join("\n\n") }
    
    trait :invalid do
      title { nil }
    end
  end
end

posts_routing_spec.rb

# frozen_string_literal: true

# spec/routing/posts_routing_spec.rb

RSpec.describe PostsController, type: :routing do
  describe 'routing' do
    # index
    it 'routes GET /posts to posts#index' do
      expect(get: '/posts').to route_to 'posts#index'
    end
    
    # show
    it 'routes GET /posts/1 to posts#show' do
      expect(get: '/posts/1').to route_to 'posts#show', id: '1'
    end
    
    # new
    it 'routes GET /posts/new to posts#new' do
      expect(get: '/posts/new').to route_to 'posts#new'
    end
    
    # edit
    it 'routes GET /posts/1/edit to posts#edit' do
      expect(get: '/posts/1/edit').to route_to 'posts#edit', id: '1'
    end
    
    # create
    it 'routes POST /posts to posts#create' do
      expect(post: '/posts').to route_to 'posts#create'
    end
    
    # update
    it 'routes PATCH /posts/1 to posts#update' do
      expect(patch: '/posts/1').to route_to 'posts#update', id: '1'
    end

    it 'routes PUT /posts/1 to posts#update' do
      expect(put: '/posts/1').to route_to 'posts#update', id: '1'
    end
    
    # destroy
    it 'routes DELETE /posts/1 to posts#destroy' do
      expect(delete: '/posts/1').to route_to 'posts#destroy', id: '1'
    end
  end
end

posts_spec.rb

# frozen_string_literal: true

# spec/requests/posts_spec.rb

RSpec.describe '/posts', type: :request do
  # index
  describe 'GET posts_url' do
    it 'renders a successful response' do
      get posts_url
      expect(response).to be_successful
    end
  end

  # show
  describe 'GET post_url' do
    it 'renders a successful response' do
      post = create :post
      get post_url post
      expect(response).to be_successful
    end
  end

  # new
  describe 'GET new_post_url' do
    it 'renders a successful response' do
      get new_post_url
      expect(response).to be_successful
    end
  end

  # edit
  describe 'GET /posts/:id/edit' do
    it 'renders a successful response' do
      post = create :post
      get edit_post_url post
      expect(response).to be_successful
    end
  end

  # create
  describe 'POST posts_url' do
    context 'when post params are valid' do
      let(:valid_post_params) { attributes_for :post }

      it 'creates a new post' do
        expect {
          post posts_url, params: { post: valid_post_params }
        }.to change(Post, :count).by 1
      end

      it 'redirects to the post url' do
        post posts_url, params: { post: valid_post_params }
        expect(response).to redirect_to post_url(Post.last)
      end
    end

    context 'when post params are invalid' do
      let(:invalid_post_params) { attributes_for :post, :invalid }

      it 'does not create a new post' do
        expect {
          post posts_url, params: { post: invalid_post_params }
        }.to change(Post, :count).by 0
      end

      it 'renders a successful response' do
        post posts_url, params: { post: invalid_post_params }
        expect(response).to be_successful
      end
    end
  end

  # update
  describe 'PATCH post_url' do
    context 'when post params are valid' do
      let(:valid_post_params) { attributes_for :post }

      it 'updates the post' do
        post = create :post
        patch post_url(post), params: { post: valid_post_params }
        post.reload
        skip '...'
      end

      it 'redirects to the post url' do
        post = create :post
        patch post_url(post), params: { post: valid_post_params }
        post.reload
        expect(response).to redirect_to post_url(post)
      end
    end

    context 'when post params are invalid' do
      let(:invalid_post_params) { attributes_for :post, :invalid }

      it 'does not update the post' do
        skip '...'
      end

      it 'renders a successful response' do
        post = create :post
        patch post_url(post), params: { post: invalid_post_params }
        expect(response).to be_successful
      end
    end
  end

  # destroy
  describe 'DELETE post_url' do
    it 'destroys the post' do
      post = create :post
      expect {
        delete post_url post
      }.to change(Post, :count).by -1
    end

    it 'redirects to the posts url' do
      post = create :post
      delete post_url post
      expect(response).to redirect_to posts_url
    end
  end
end

rails_helper.rb

# frozen_string_literal: true

# spec/rails_helper.rb

require 'spec_helper'

ENV['RAILS_ENV'] ||= 'test'

require File.expand_path('../config/environment', __dir__)

abort('The Rails environment is running in production mode!') if Rails.env.production?

require 'rspec/rails'

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

begin
  ActiveRecord::Migration.maintain_test_schema!
rescue ActiveRecord::PendingMigrationError => e
  puts e.to_s.strip
  exit 1
end

RSpec.configure do |config|
  config.filter_rails_from_backtrace!
  config.fixture_path = "#{::Rails.root}/spec/fixtures"
  config.infer_spec_type_from_file_location!
  config.use_transactional_fixtures = true
end

shoulda_matchers.rb

# frozen_string_literal: true

# spec/support/shoulda_matchers.rb

Shoulda::Matchers.configure do |config|
  config.integrate do |with|
    with.test_framework :rspec
    with.library :rails
  end
end

show.html.erb_spec.rb

# frozen_string_literal: true

# spec/views/posts/show.html.erb_spec.rb

require 'rails_helper'

RSpec.describe 'posts/show.html.erb', type: :view do
  before do
    assign :post, create(:post)
  end
  
  it 'renders ...' do
    # render
    # assert_select
    # expect(rendered).to match()
    skip '...'
  end
end

spec_helper.rb

# frozen_string_literal: true

# spec/spec_helper.rb

RSpec.configure do |config|
  config.expect_with :rspec do |expectations|
    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
  end
  
  config.mock_with :rspec do |mocks|
    mocks.verify_partial_doubles = true
  end
  
  config.shared_context_metadata_behavior = :apply_to_host_groups
end