Rails 6 & deliver_later doesn't affect ActionMailer::Base.deliveries

Question

After upgrading to Rails 6 I am noticing that default mailer's .deliver_later is not working the same as in Rails 5.

Configuration:

config.active_job.queue_adapter = :inline

When running Mailer.register_email(...).deliver_later - nothing is stored in ActionMailer::Base.deliveries. This array gets filled if I run perform_enqueued_jobs - it seams like queue_adapter = :inline doesn't work the way I expect it to work.

If I run Mailer.send(...).deliver_now then ActionMailer::Base.deliveries has proper value in it.

Any idea why this is happening and how to solve this?

Answer 1

I had same problem in my tests. A search on the Internet yielded nothing, so I started experimenting.

I tried wrapping the call method of sending mail in

assert_emails 1 do
  Mailer.register_email(...).deliver_later
end

After that, ActionMailer::Base.deliveries populated correctly.