Test engine

Skill igmarin/rails-agent-skills/skills/engines/test-engine

This is my personal configuration of skills as a Ruby on Rails Dev

Install

npx -y skills add igmarin/rails-agent-skills --skill test-engine

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

One thing to look at

22 stars22 stars. Stars are a popularity signal and not a quality one, but at this level it is likely that nobody has read this closely except its author, and you would be relying on your own review.

What its author says it does

Copied from the file, not written here

Use when writing and configuring RSpec tests for Rails engines — must ensure that a dummy app exists for testing, add the smallest integration test that proves mounting and boot and verify it passes before continuing, and run the full test suite via bundle exec rspec to verify all specs pass. Key capabilities: request and routing specs with namespace scoping, generator idempotency, configuration testing.

The file declares its own license as MIT. That is the author’s claim about this one file, and it is not the same thing as the license GitHub reports for the repository, which is listed with the other numbers below.

SKILL.md

3.7 KB, as published. Nobody here has run it

Test Engine

HARD-GATE

EVERY engine MUST have a dummy app for testing.
If it doesn't exist, generate it:
cd my_engine && bundle exec rails plugin new . --dummy-path=spec/dummy --skip-git

Validate the dummy app boots before proceeding:
cd spec/dummy && bundle exec rails runner "puts 'Boot OK'"

If this fails, check the engine's `engine.rb` initializer order and ensure the engine is correctly mounted in `spec/dummy/config/routes.rb` before writing any specs.

Core Process

Identify the engine type and public behaviors.
Add the smallest integration test that proves mounting and boot work. Verify it passes before continuing — if it fails, check engine.rb initializer order and mount configuration.
Add request, routing, configuration, and generator coverage as needed.
Add regression tests for coupling bugs before refactoring.
Run the full test suite (bundle exec rspec) to verify all specs pass.

Minimal request spec to prove the engine mounts:

# spec/requests/my_engine/root_spec.rb
require 'rails_helper'

RSpec.describe 'MyEngine mount', type: :request do
  it 'returns ok for the engine root' do
    get my_engine.root_path
    expect(response).to have_http_status(:ok)
  end
end

Configuration spec (engine respects host config):

# spec/my_engine/configuration_spec.rb
RSpec.describe MyEngine::Configuration do
  around do |example|
    original = MyEngine.config.widget_count
    MyEngine.config.widget_count = 3
    example.run
    MyEngine.config.widget_count = original
  end

  it 'uses configured value' do
    expect(MyEngine.config.widget_count).to eq(3)
  end
end

Advanced Coverage Patterns

Namespace-scoped routing spec:

# spec/routing/my_engine/widgets_routing_spec.rb
require 'rails_helper'

RSpec.describe MyEngine::WidgetsController, type: :routing do
  routes { MyEngine::Engine.routes }

  it 'routes GET /widgets to widgets#index' do
    expect(get: '/widgets').to route_to('my_engine/widgets#index')
  end
end

Generator idempotency spec:

# spec/generators/my_engine/install_generator_spec.rb
require 'rails_helper'
require 'generators/my_engine/install/install_generator'

RSpec.describe MyEngine::Generators::InstallGenerator, type: :generator do
  destination File.expand_path('../tmp', __dir__)

  before { prepare_destination }

  it 'generates the initializer' do
    run_generator
    expect(file('config/initializers/my_engine.rb')).to exist
  end

  it 'is idempotent on re-run' do
    run_generator
    expect { run_generator }.not_to raise_error
    expect(file('config/initializers/my_engine.rb')).to exist
  end
end

Output Style

When completing engine test setup, summarise results as:

Engine Test Report — [Engine Name]
- Dummy app: [location], boot ✓, migrations ✓
- Specs: mounting ✓, generators ✓, core (<n> examples, 0 failures)
- Suite: bundle exec rspec — <n> examples, 0 failures

Integration

Skill	When to chain
create-engine	When structuring the engine for testability or adding configuration seams
review-engine	When validating test coverage adequacy or identifying gaps
write-tests	When improving spec structure, matchers, or shared examples