Simple Improvements and Testing of a Rails Controller

Simple case how to improve your controller in a Rails application

Step 1. Route to the main page

First I want to check #root route of an App

I go to config/routes.rb and see

Rails.application.routes.draw do
  root to: 'root#index'
end

Step 2. Checking the controller

I visit the controller app/controllers/root_controller.rb

class RootController < ActionController::Base
  def index
    @mailto = "hello@company.com"
    @blogs = Blog
             .published
             .limit(10)
  end
end

Step 3. How to Improve

I see a way to improve the controller. I want to move numbers and strings in constants.

Rule: Do not keep Magic numbers in your code. Always move it constants!

class RootController < ActionController::Base
  MAIN_EMAIL = "hello@company.com"
  INDEX_BLOGS_COUNT = 10

  def index
    @mailto = MAIN_EMAIL
    @blogs = Blog
             .published
             .limit(INDEX_BLOGS_COUNT)
  end
end

Step 4. Adding tests

In my app test environment is already set up. I will just improve existed tests a bit.

require 'rails_helper'

RSpec.describe RootController type: :controller do
  describe 'Constants' do
    it "has expected INDEX_BLOGS_COUNT" do
      expect(RootController::INDEX_BLOGS_COUNT).to eq 10
    end

    it "has expected MAIN_EMAIL" do
      expect(RootController::MAIN_EMAIL).to
        eq("hello@company.com")
    end
  end

  describe '#index' do
    let!(:published_blogs) { create_list :blogs, 3, :published }

    before do
      get :index
    end

    it do
      expect(response).to render_template(:index)
    end

    it do
      expect(assigns(:blogs).map(&:id)).to
        match_array(published_blogs.map(&:id))
    end

    it { expect(assigns(:mailto)).to eq RootController::MAIN_EMAIL }
  end
end

Step 5. Running the test case

bundle exec rspec spec/controllers/root_controller_spec.rb

That is it!
Happy Coding!

Blog

Simple Improvements and Testing of a Rails Controller

Ilya N. Zykin

Step 1. Route to the main page

Step 2. Checking the controller

Step 3. How to Improve

Step 4. Adding tests

Step 5. Running the test case

Join Our Newsletter. No Spam, Only the good stuff.

Related