[RUBY] About method matchers used in model unit test code (RSpec)

Method list (partial)

①valid? A method that means "correct" in Japanese and determines "whether it is correct". Basically used for abnormal system testing. If the created data is saved correctly, ** true ** is returned, and if it is not saved, ** false ** is returned. If it is not saved, it also generates a ** error message ** indicating "why not saved".

users.rb

FactoryBot.define do
  factory :user do
    nickname              { Faker::Name.initials(number: 2) }
    email                 { Faker::Internet.free_email }
    password              { Faker::Internet.password(min_length: 6) }
    password_confirmation { password }
  end
end

user_spec.rb

require 'rails_helper'
describe User, type: :model do
  before do
    @user = FactoryBot.build(:user)
  end

  describe 'New user registration' do
    context 'When new registration is successful' do
    #(abridgement)
    end

    context 'When new registration does not go well' do
      it "Cannot register if the nickname is empty" do
        @user.nickname = ''
        @user.valid? # <=this part
        # => false
      end
    end
  end
end

② errors and hull_messages

** errors ** is a method that displays the errors of the data judged by ** valid? **. ** hull_messages ** is a method for outputting error messages. Basically, these two methods are used in combination.

users.rb

FactoryBot.define do
  factory :user do
    nickname              { Faker::Name.initials(number: 2) }
    email                 { Faker::Internet.free_email }
    password              { Faker::Internet.password(min_length: 6) }
    password_confirmation { password }
  end
end

user_spec.rb

require 'rails_helper'
describe User, type: :model do
  before do
    @user = FactoryBot.build(:user)
  end

  describe 'New user registration' do
    context 'When new registration is successful' do
    #(abridgement)
    end

    context 'When new registration does not go well' do
      it "Cannot register if the nickname is empty" do
        @user.nickname = ''
        @user.valid?
        expect(@user.errors.full_messages).to include("Please enter a nickname") # <=this part
      end
    end
  end
end

After this, I will introduce it again, but ** include ** is a matcher that has the meaning of "include" in Japanese and can confirm "whether the character string Y is included in X". is.

What is Matcha?

A method that compares the expected data with the actual data and returns the result ** matched ** or ** not matched **.

Matcha list (partial)

①include ** include ** is a matcher that has the meaning of "include" in Japanese and allows you to check "whether or not the character string Y is included in X".

users.rb

FactoryBot.define do
  factory :user do
    nickname              { Faker::Name.initials(number: 2) }
    email                 { Faker::Internet.free_email }
    password              { Faker::Internet.password(min_length: 6) }
    password_confirmation { password }
  end
end

user_spec.rb

require 'rails_helper'
describe User, type: :model do
  before do
    @user = FactoryBot.build(:user)
  end

  describe 'New user registration' do
    context 'When new registration is successful' do
    #(abridgement)
    end

    context 'When new registration does not go well' do
      it "Cannot register if the nickname is empty" do
        @user.nickname = ''
        @user.valid?
        expect(@user.errors.full_messages).to include("Please enter a nickname") # <=this part
      #        <            X           >　　 　　　     <           Y         > 
    end
  end
end

②be_valid ** be_valid ** is a method that determines that an instance of expect is saved correctly. Basically used in normal testing.

users.rb

FactoryBot.define do
  factory :user do
    nickname              { Faker::Name.initials(number: 2) }
    email                 { Faker::Internet.free_email }
    password              { Faker::Internet.password(min_length: 6) }
    password_confirmation { password }
  end
end

user_spec.rb

describe 'New user registration' do
  context 'When new registration is successful' do
    it "You can register if you have a nickname, email address, password, and password (for confirmation)." do
      expect(@user).to be_valid
    end
  end

  context 'When new registration does not go well' do
  #(abridgement)
  end
end