How do you test a dummy rails app when writing a gem?

Question

I'm writing a gem that integrates with rails, and I want to be able to test a dummy app with rspec inside my gem's test suite.

The issue comes up when I test if my dummy rails app loads / a couple modules via rspec spec/integration/rails/load_path_spec.rb

So far, this is what I have:

# spec/support/rails_app/config/environment.rb

# Load the Rails application.
require File.expand_path('../application', __FILE__)

# Load the gem
require 'skinny_controllers'

# Initialize the Rails application.
Rails.application.initialize!

Me test looks like this:

require 'rails_helper'

describe 'definitions of operations and policies' do
  it 'loads operations' do
    is_defined = defined? EventOperations
    expect(is_defined).to be_truthy
  end

  it 'loads policies' do
    is_defined = defined? EventPolicy
    expect(is_defined).to be_truthy
  end
end

rails_helper looks like this:

require 'rails/all'

require 'factory_girl'
require 'factory_girl_rails'
require 'rspec/rails'

require 'support/rails_app/config/environment'

ActiveRecord::Migration.maintain_test_schema!

# set up db
# be sure to update the schema if required by doing
# - cd spec/rails_app
# - rake db:migrate
ActiveRecord::Schema.verbose = false
load "support/rails_app/db/schema.rb" # use db agnostic schema by default


require 'support/rails_app/factory_girl'
# require 'support/rails_app/factories'
require 'spec_helper'

And spec_helper looks like this:

require 'rubygems'
require 'bundler/setup'

require 'pry-byebug' # binding.pry to debug!
require 'awesome_print'

# Coverage
ENV['CODECLIMATE_REPO_TOKEN'] = ''
require 'codeclimate-test-reporter'
CodeClimate::TestReporter.start if ENV['TRAVIS']


# This Gem
require 'skinny_controllers'

$LOAD_PATH.unshift Dir[File.dirname(__FILE__) + '/support/operations'].first
$LOAD_PATH.unshift Dir[File.dirname(__FILE__) + '/support/policies'].first
Dir[File.dirname(__FILE__) + '/support/**/*.rb'].each do |file|
  # skip the dummy app
  next if file.include?('support/rails_app')

  require file
end

# This file was generated by the `rspec --init` command. Conventionally, all
# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
# Require this file using `require "spec_helper"` to ensure that it is only
# loaded once.
#
# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
RSpec.configure do |config|
  config.run_all_when_everything_filtered = true
  config.filter_run :focus
  # Run specs in random order to surface order dependencies. If you find an
  # order dependency and want to debug it, you can fix the order by providing
  # the seed, which is printed after each run.
  #     --seed 1234
  config.order = 'random'
end

it seems like, half of the time, when I run rspec, all of the tests pass.

If anyone is curious, my repository is here: https://github.com/NullVoxPopuli/skinny_controllers

Answer 1

Here is how I ended up testing a rails app here is the gem where I have a dummy rails app

In whatever spec files you want to test your rails app, you'll want to require a new file, which I called rails_helper.rb

require 'rails/all'

require 'factory_girl'
require 'factory_girl_rails'
require 'rspec/rails'

require 'support/rails_app/config/environment'

ActiveRecord::Migration.maintain_test_schema!

# set up db
# be sure to update the schema if required by doing
# - cd spec/support/rails_app
# - rake db:migrate
ActiveRecord::Schema.verbose = false
load 'support/rails_app/db/schema.rb' # db agnostic

require 'support/rails_app/factory_girl'
require 'spec_helper'

And then in the spec/support folder, generate your rails app there. Mine is at: 'spec/support/rails_app'. In here, the rails app can be very slimmed down compared to what the default scaffold generates.

I did have to make a change to the app, in config/environment.rb

# Load the Rails application.
require File.expand_path('../application', __FILE__)

# gem should be required here
require 'skinny_controllers' 

# Initialize the Rails application.
Rails.application.initialize!

And for the database.yml,

default: &default
  adapter: sqlite3
  pool: 5
  timeout: 5000

development:
  <<: *default
  database: db/development.sqlite3

test:
  <<: *default
  database: db/test.sqlite3

The db setting could probably be changed to use in-memory sqlite, if one so desired.

Hopefully that's it. If I missed anything, I'll update this answer.