Perform email jobs in #assert_emails

[gmcgibbon]

Summary

Currently, ActionMailer's test helpers for asserting emails do not perform enqueued mail jobs. With this change, code like:

assert_emails(1) do
  perform_enqueud_jobs(only: ActionMailer::DeliveryJob) do
    SomeMailer.send_mail.deliver_later
  end
end

can be shortened to:

assert_emails(1) { SomeMailer.send_mail.deliver_later }

Are there any strong feelings against this change? What would be a scenario where this would not be wanted?

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[LilyReile]

Hey, @gmcgibbon, do you know what commit made this change necessary? Rails 5 pushes to ActionMailer::Base.deliveries without this.

[gmcgibbon]

@DylanReile That's probably related to the queue adapter you have configured for your app's test environment. The default one (async) doesn't performa jobs right away.

[LilyReile]

@gmcgibbon We're on config.active_job.queue_adapter = :test which I believe is the default since Rails 5. It works in Rails 5, but fails in Rails 6 without perform_enqueued_jobs. I was just curious about what happened in the interim.

[gmcgibbon]

We're on config.active_job.queue_adapter = :test which I believe is the default since Rails 5.

Generating a new app on Rails 5 and looking at the git history I don't see config.active_job.queue_adapter = :test ever being in test.rb by default. 🤔

[gaffneyc]

Seems this is related to #37270 and the need for it was introduced by 96218b4