So, you've started using the magic that is StimulusReflex. Neat, us too!

At this time, there aren't official testing helpers in the StimulusReflex library. We wanted to unit-test our reflexes, so we thought we share what we've been working on.

Things we'd like to add/improve on:

• MiniTest support
• Integration style testing?
• The ability to run assertions/expectations against the HTML re-rendered by a reflex
  • expect(subject.to_html).to include('Hi, I rendered from a Reflex!')
• Session is stubbed out (Rspec) right now, but we'd love to find a way to support sessions in testing
• Things you find useful that we can't think of, yet

Add this line to your application's Gemfile:

gem 'stimulus_reflex_testing'

Both Rails 6 and RSpec Rails 4 introduce the action-cable-testing library. If you're using Rails 5.2 and a version of RSpec Rails lower than 4, include the action-cable-testing gem in your Gemfile.

gem 'stimulus_reflex_testing'
gem 'action-cable-testing'

And then execute:

$ bundle install

Require the library into your rails_helper:

require 'stimulus_reflex_testing/rspec'

Rspec tests include the reflex testing functionality when type: :reflex is provided. If this type is not provided, your Reflex tests won't work.

To build an instance of your reflex with the required setup handled (channel, url, element, etc) you can use the build_reflex method.

# With a valid URL so StimulusReflex can build the correct request
build_reflex(url: posts_url)

# Does your test rely on a `current_user` (or similar) defined in `ApplicationCable::Connection`?
build_reflex(url: posts_url, connection: { current_user: create(:user) })

# Do you rely on form params?
build_reflex(url: edit_post_url(post), params: { post: { title: 'A new title!' } })

# Need to give your element some data?
reflex = build_reflex(url: posts_url)
reflex.element.value = "Hello"
reflex.element.dataset.id = "123"

To unit test a reflex, we provide a method (when using build_reflex) called #run. This method takes a method name, and any arguments.

reflex = build_reflex(url: posts_url)
reflex.run(:method, arg1, arg2)

Why can't I just call the method directly?

You're more than welcome to call the method directly. But, be advised you will lose callbacks. If you need to run before_reflex (etc) use the run method.

#run is a wrapper around the underlying #process method in StimulusReflex that runs callbacks.

To grab an instance variable set by a reflex, you can use the #get method when using a reflex built with build_reflex.

# app/reflexes/post_reflex.rb
class PostReflex < ApplicationReflex
  def find_post
    @post = Post.find(params[:id])
  end
end

reflex = build_reflex(url: edit_post_url(post), params: { id: post.id })
reflex.run(:find_post)
reflex.get(:post) #=> returns the @post instance variable

# app/reflexes/post_reflex.rb
class PostReflex < ApplicationReflex
  def validate
    @post = Post.find(element.dataset.post_id)
    @post.validate
  end
end

# spec/reflexes/post_reflex_spec.rb
require 'rails_helper'

RSpec.describe PostReflex, type: :reflex do
  let(:post) { create(:post) }
  let(:reflex) { build_reflex(url: edit_post_url(post)) }

  describe '#validate' do
    subject { reflex.run(:validate) }

    before do
      reflex.element.dataset.post_id = post.id
      subject
    end

    it 'should find the post' do
      expect(reflex.get(:post)).to eq(post)
    end

    it 'should validate the post' do
      expect(reflex.get(:post).errors).to be_present
    end
  end
end

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/podia/stimulus_reflex_testing. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in the StimulusReflexTesting project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.