config.ru

require 'rubygems'
require 'bundler'

Bundler.require :default, :development

Combustion.initialize!
run Combustion::Application

engine.rb

require 'rails'
require 'combustion'
require 'active_record'

module Convertor
  class Engine < ::Rails::Engine
    isolate_namespace Convertor
  end
end

Gemfile

source "http://rubygems.org"

# Declare any dependencies that are still in development here instead of in
# your gemspec. These might include edge Rails or gems from your path or
# Git. Remember to move these dependencies to your gemspec before releasing
# your gem to rubygems.org.
group :test do
  gem 'combustion'
  gem 'sqlite3'
  gem 'activerecord'
  gem 'actionpack' # action_controller, action_view
  gem 'sprockets'
  gem "rspec-rails", "~> 2.0"
  gem 'debugger'
end

# Declare your gem's dependencies in convertor.gemspec.
# Bundler will treat runtime dependencies like base dependencies, and
# development dependencies will be added by default to the :development group.
gemspec

gemspec

$:.push File.expand_path("../lib", __FILE__)

# Maintain your gem's version:
require "convertor/version"

# Describe your gem and declare its dependencies:
Gem::Specification.new do |s|
  s.name        = "convertor"
  s.version     = Convertor::VERSION
  s.authors     = ["Scott"]
  s.summary     = "This engine provides a variety of tools to convertor project data to and from different formats"

  s.files = Dir["{app,config,db,lib}/**/*"] + ["MIT-LICENSE", "Rakefile", "README.rdoc"]

  s.add_dependency "rails", "~> 3.2.12"
end

spec_helper.rb

require 'rubygems'
require 'bundler/setup'

require 'combustion'

Combustion.initialize! :active_record, :action_controller, :action_view

require 'rspec/rails'

RSpec.configure do |config|
  # 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

Stacktrace

/Users/scott/Code/pimms/engines/convertor/lib/convertor/engine.rb:2:in `<module:Convertor>': uninitialized constant Rails (NameError)
  from /Users/scott/Code/pimms/engines/convertor/lib/convertor/engine.rb:1:in `<top (required)>'
	from /Users/scott/Code/pimms/engines/convertor/lib/convertor.rb:1:in `require'
	from /Users/scott/Code/pimms/engines/convertor/lib/convertor.rb:1:in `<top (required)>'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
	from /Users/scott/Code/pimms/engines/convertor/config.ru:4:in `block in <main>'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/lib/rack/builder.rb:51:in `instance_eval'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/lib/rack/builder.rb:51:in `initialize'
	from /Users/scott/Code/pimms/engines/convertor/config.ru:in `new'
	from /Users/scott/Code/pimms/engines/convertor/config.ru:in `<main>'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/lib/rack/builder.rb:40:in `eval'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/lib/rack/builder.rb:40:in `parse_file'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/lib/rack/server.rb:200:in `app'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/lib/rack/server.rb:304:in `wrapped_app'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/lib/rack/server.rb:254:in `start'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/lib/rack/server.rb:137:in `start'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/gems/rack-1.4.5/bin/rackup:4:in `<top (required)>'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/bin/rackup:19:in `load'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/bin/rackup:19:in `<main>'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/bin/ruby_noexec_wrapper:14:in `eval'
	from /Users/scott/.rvm/gems/ruby-1.9.3-p327/bin/ruby_noexec_wrapper:14:in `<main>'