Capybara tests - No port in JS assets

Question

Writing some capybara integration/feature tests for my Rails 5 app & they keep failing b/c none of the JS loads. When I looked into it, I saw that in my test env, the script looks like this:

<script src="/assets/application.debug-c0cceddfe5721264a37a27717e21b167d46fd27617e66e210764c0dfd36b5992.js"></script>

But when it's loaded with selenium, the script looks like this:

<script src="http://127.0.0.1/assets_test/application-5c233b506cd224705939cbe7104615eba3c0f51d572dba60e074395a6346472a.js"></script>

Notice how it now has the host explicit. However, the test runs on a separate port, for example :56789, so the test JS doesn't load since the port isn't specified.

When I go to the link in the above src in the test environment, I get nothing. However, when I add the port number being used for this test, I see the JS file just fine.

What gives? To properly run my integration test, I need to be able to load this JS, and I'm at a complete loss on how to do that.

---

Here is my configuration:

test.rb

Rails.application.configure do
  config.action_controller.asset_host = "file://#{::Rails.root}/public"
  config.assets.prefix = 'assets_test'
  config.action_controller.asset_host = "127.0.0.1"
  config.serve_static_assets = true
  config.action_mailer.default_url_options = { host: 'localhost', port: 3000 }
  config.cache_classes = false
  config.action_view.cache_template_loading = true
  config.eager_load = false
  config.public_file_server.enabled = true
  config.public_file_server.headers = {
    'Cache-Control' => "public, max-age=#{1.hour.to_i}"
  }
  config.consider_all_requests_local       = true
  config.action_controller.perform_caching = false
  config.cache_store = :null_store
  config.action_dispatch.show_exceptions = false
  config.action_controller.allow_forgery_protection = false
  config.active_storage.service = :test
  config.action_mailer.perform_caching = false
  config.action_mailer.delivery_method = :test
  config.active_support.deprecation = :stderr
end

Figured it out. Commented these lines out and it works:

#config.action_controller.asset_host = "file://#{::Rails.root}/public"
  #config.assets.prefix = 'assets_test'
  #config.action_controller.asset_host = "127.0.0.1"
  #config.serve_static_assets = true

Not sure how they ended up in my code in the first place.