Rspec ActiveJob and ActionMailer


Since Rails 4.2, ActionMailer is integrate with ActiveJob. So this code


create a queue ‘mailers’ and add it automatically, So, no class
UserMailerWorker is needed.
How can I test without class worker ?
Before I do

expect(UserMailerWorker).to have_queue_size_of(1)

Whats can I do now ? How test directly with queue name ?