Mail::Matchers example

use_mail_matchers_when_test_action_mailer.rb

# frozen_string_literal: true

require 'bundler/inline'

gemfile do
  source 'https://rubygems.org'

  gem 'actionmailer', '6.0.3.4'
  gem 'rspec', '3.10.0'
end

require 'action_mailer'

ActionMailer::Base.delivery_method = :test

class NotificationsMailer < ActionMailer::Base
  default from: '[email protected]'

  def signup
    mail(to: '[email protected]', subject: 'Signup') do |format|
      format.text { render plain: 'Hi' }
    end
  end
end


require 'rspec/autorun'

RSpec.configure do |config|
  config.include Mail::Matchers, type: :mailer
end

RSpec.describe NotificationsMailer, type: :mailer do
  before do
    ActionMailer::Base.deliveries.clear
  end

  describe '#signup' do
    # @see: https://relishapp.com/rspec/rspec-rails/v/3-9/docs/mailer-specs/mailer-spec
    context 'when using RSpec mailer examples' do
      subject(:mail) { described_class.signup }

      it 'renders the headers' do
        expect(mail.subject).to eq('Signup')
        expect(mail.to).to eq(['[email protected]'])
        expect(mail.from).to eq(['[email protected]'])
      end

      it 'renders the body' do
        expect(mail.body.encoded).to match('Hi')
      end

      it 'sends the mail' do
        expect { mail.deliver_now }.to change { ActionMailer::Base.deliveries.count }
      end
    end

    # @see: https://github.com/mikel/mail#using-mail-with-testing-or-specing-libraries
    context 'when using Mail::Matchers' do
      subject(:mail) { described_class.signup.deliver_now }

      it { is_expected.to have_sent_email }
      it { is_expected.to have_sent_email.from('[email protected]') }
      it { is_expected.to have_sent_email.to('[email protected]') }
      it { is_expected.to have_sent_email.with_subject('Signup') }
      it { is_expected.to have_sent_email.with_body('Hi') }
    end
  end
end

$ ruby ./use_mail_matchers_when_test_action_mailer.rb -fd

NotificationsMailer
  #signup
    when using RSpec mailer examples
      renders the headers
      renders the body
      sents the mail
    when using Mail::Matchers
      is expected to send a matching email
      is expected to send a matching email
      is expected to send a matching email
      is expected to send a matching email
      is expected to send a matching email

Finished in 0.27858 seconds (files took 0.61162 seconds to load)
8 examples, 0 failures