It's very easy to forget to add `require 'rails_helper'` at the top of every core/plugin spec file, and omissions can cause some very confusing/sporadic errors.
By setting this flag in `.rspec`, we can remove the need for `require 'rails_helper'` entirely.
Zeitwerk simplifies working with dependencies in dev and makes it easier reloading class chains.
We no longer need to use Rails "require_dependency" anywhere and instead can just use standard
Ruby patterns to require files.
This is a far reaching change and we expect some followups here.
This change both speeds up specs (less strings to allocate) and helps catch
cases where methods in Discourse are mutating inputs.
Overall we will be migrating everything to use #frozen_string_literal: true
it will take a while, but this is the first and safest move in this direction
Since rspec-rails 3, the default installation creates two helper files:
* `spec_helper.rb`
* `rails_helper.rb`
`spec_helper.rb` is intended as a way of running specs that do not
require Rails, whereas `rails_helper.rb` loads Rails (as Discourse's
current `spec_helper.rb` does).
For more information:
https://www.relishapp.com/rspec/rspec-rails/docs/upgrade#default-helper-files
In this commit, I've simply replaced all instances of `spec_helper` with
`rails_helper`, and renamed the original `spec_helper.rb`.
This brings the Discourse project closer to the standard usage of RSpec
in a Rails app.
At present, every spec relies on loading Rails, but there are likely
many that don't need to. In a future pull request, I hope to introduce a
separate, minimal `spec_helper.rb` which can be used in tests which
don't rely on Rails.
