Testing code in a Rails engine with RSpec - ruby-on-rails

Question

I'm trying to do something seemingly simple but it's proven rather hard.
I want to write tests using RSpec for classes that I've put in the lib directory of a Rails Engine.
Here are exactly the steps I'm using:
rails plugin new mygem -T --mountable --full --dummy-path=spec/dummy
Then I cd mygem; vim mygem.gemspec
I add the following line to mygem.gemspec:
s.add_development_dependency "rspec-rails"
I run bundle install; rails generate rspec:install
Then I edit ~/mygem/lib/mygem/engine.rb adding the following:
module Mygem
class Engine < ::Rails::Engine
isolate_namespace Mygem
config.generators do |g|
g.test_framework :rspec
end
end
end
I create a very simple class in the lib directory, ~/mygem/lib/mygem/something.rb
and add the following:
module Mygem
class Something
def hi
"hi"
end
end
end
Create a test file ~/mygem/spec/something_spec.rb
then add the following:
require 'rails_helper'
describe Mygem::Something do
it 'says hi' do
s = Mygem::Something.new
expect(s.hi).to eq('hi')
end
end
And boom, I get the following output:
rspec
~/Documents/mygem/spec/rails_helper.rb:3:in `require': cannot load such file -- ~/Documents/mygem/config/environment (LoadError)
from ~/Documents/mygem/spec/rails_helper.rb:3:in `<top (required)>'
from ~/Documents/mygem/spec/something_spec.rb:1:in `require'
from ~/Documents/mygem/spec/something_spec.rb:1:in `<top (required)>'
from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/lib/rspec/core/configuration.rb:1327:in `load' from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/lib/rspec/core/configuration.rb:1327:in `block in load_spec_files'
from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/lib/rspec/core/configuration.rb:1325:in `each'
from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/lib/rspec/core/configuration.rb:1325:in `load_spec_files'
from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/lib/rspec/core/runner.rb:102:in `setup'
from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/lib/rspec/core/runner.rb:88:in `run'
from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/lib/rspec/core/runner.rb:73:in `run'
from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/lib/rspec/core/runner.rb:41:in `invoke'
from ~/.rvm/gems/ruby-2.2.2/gems/rspec-core-3.3.2/exe/rspec:4:in `<top (required)>'
from ~/.rvm/gems/ruby-2.2.2/bin/rspec:23:in `load'
from ~/.rvm/gems/ruby-2.2.2/bin/rspec:23:in `<main>'
from ~/.rvm/gems/ruby-2.2.2/bin/ruby_executable_hooks:15:in `eval'
from ~/.rvm/gems/ruby-2.2.2/bin/ruby_executable_hooks:15:in `<main>'
Any tips as to what I may be doing incorrectly?
Thanks in advance!

Answer 1

It looks like your rails_helper is looking for an environment.rb file to load, which doesn't exist in a Rails engine. It does, however, exist in your dummy app, which is what RSpec is run against.
Try adding this into the top of your rails_helper file:
require File.expand_path("../dummy/config/environment.rb", __FILE__)

Answer 2

Finally got it working after the following steps (thanks ccai for the suggestion):
in rails_helper.rb:
# Comment this line:
# require File.expand_path('../../config/environment', __FILE__)
require File.expand_path("../dummy/config/environment.rb", __FILE__)
then in lib/mygem.rb
require "mygem/something"
Works!