Perform Enqueued Mail Job in Rails 6 Tests

test_helper.rb

# Extend in your test_helper.rb or any other `/support` setup you have.

class ActiveSupport::TestCase
  # === NOTICE: 
  #     Ensure you have included `ActionMailer::TestHelper` in the test class ..
  #
  # This method performs any enqueued job during tests manually,
  # Helpful when testing the queueing of your jobs and then the result of their execution.
  #
  # === Author: (abarrak, danielpuglisi)
  # 
  # === returns: the result of the job execution.
  #
  # === example: (integration test for ActiveJob/ActionMailer)
  #
  # test "my action mailer" do
  #   post signup_url, params: @valid_params
  #   
  #   # ... other assertions ...
  #
  #   assert_enqueued_emails 1
  #   assert_enqueued_jobs 1
  # 
  #   perform_last_mail_job
  # 
  #   assert_emails 1 # make sure to empty ActionMailer::Base.deliveries after each test for correct results
  #
  #   mail = ActionMailer::Base.deliveries.last
  #   assert_not_nil mail
  #   assert_equal mail.to, [user.email]
  #   assert_equal mail.from, ["no-replay@example.com"]
  # end
  #
  # ====
  def perform_last_mail_job
    # Get last mailer job
    last_job = enqueued_jobs.first[:args]
    mailer, mail_method, delivery_method = last_job

    # Parse job arguments
    args = last_job[3]['args']
    objects = args.map{|arg| parse_aj_global_id(arg)}

    # Perform the last job
    perform_enqueued_jobs do
      ActionMailer::MailDeliveryJob.perform_now(
        mailer,
        mail_method,
        delivery_method,
        args: objects
      )
    end
  end

  private

  def parse_aj_global_id(arg)
    return nil if arg.nil?
    gid = arg['_aj_globalid']
    GlobalID::Locator.locate(gid)
  end
end