Testing model with RSpec

model test preparation

This time, we will test whether the Post model has a title column and the number of characters.

app/models/post.rb

class Post < AplicationRecord
  belongs_to :user
  validates :title, presence: true, length: {maximum: 20}
end

Create file

(1) Create a models folder and a factories folder under spec, and create a file of the model you want to test. This time create spec/models/post_spec.rb

② Enable Factroy Bot. If you use it, you can register DB and build model like user = create (: user). Create a support folder and factory_bot.rb file under spec and describe the following. Create two files, post_spec.rb user_spec.rb, to test that you can only post if the user is logged in.

spec/support/factroy_bot.rb

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

③ Edit spec/rails_helper.rb

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'
require 'support/factory_bot'

begin
  ActiveRecord::Migration.maintain_test_schema!
rescue ActiveRecord::PendingMigrationError => e
  puts e.to_s.strip
  exit 1
end
RSpec.configure do |config|
  config.fixture_path = "#{::Rails.root}/spec/fixtures"
  config.use_transactional_fixtures = true
  config.infer_spec_type_from_file_location!
  config.filter_rails_from_backtrace!
  
  
  #Not relevant in this article, but system_Description for starting chrome in headless mode in spec
  config.before(:each) do |example|
    if example.metadata[:type] == :system
      if example.metadata[:js]
        driven_by :selenium_chrome_headless, screen_size: [1400, 1400]
      else
        driven_by :rack_test
      end
    end
  end
  
  #Description about capybara
  config.include Capybara::DSL
end

Creating dummy data

spec/factories/user.rb

FactoryBot.define do
  factory :user do
    name {Faker::Name.name}
    email {Faker::Internet.email}
    password {'password'}
    password_confirmation {'password'}
  end
end

spec/factories/post.rb

FactoryBot.define do 
  factory :post do
    body {Faker::Lorem.characters(number: 20)}
    user
  end
end

Creating test code

spec/models/post_spec.rb

require 'rails_helper'

RSpec.describe 'post model test', type: :model do
  describe 'validation test' do
    #Use dummy data created by factories
    let(:user) {FactoryBot.create(:user)}
    let!(:post) {build(:post, user_id: user.id)}
    #test_Create a post and check if you can register in the blank
    subject {test_post.valid?}
    let(:test_post) {post}
    
    it 'The title column is not blank' do
      test_post.title = ''
      is_expected.to eq false;
    end

    it 'False if 21 characters or more' do
      post.title = Faker::Lorem.characters(number: 21)
      expect(post).to eq false;
    end
  end
end

Run RSpec

$ bin/rspec spec/models/post_spec.rb