Developing Discourse Plugins - Part 6 - Add acceptance tests

I’m trying to follow this guide, but I’m getting stuck right at the beginning: I can’t access /qunit at all. (This also seems related to the Beginners Guide to Install Discourse on Ubuntu for Development, which is basically the approach I’m using to deploying Discourse on my local machine for learning about development, but this guide is the prompt that triggered my obstacle, so I thought I’d put it here.) Attempting to access it gives a “That page doesn’t exist or is private” response.

The controller for the /qunit route (discourse/qunit_controller.rb at 166fe3bb34f99bd0baa613726486ce0f13c7a992 · discourse/discourse · GitHub) mentions that it is # only used in non-ember-cli test / dev (the comment before that method), so I’ve tried running the instance with RAILS_ENV=test bundle exec rails server, but EmberCli.enabled? is still true.

What approach are you all using to run a local development server such that we can actually access /qunit (which probably involves disabling EmberCLI)? (I certainly may be missing something obvious.)