RSpec helper (spec_helper.rb) for a Rails Engine setup, as per http://stackoverflow.com/questions/7452037/testing-rails-3-1-mountable-engine-with-rspec

rails-engine-rspec-helper.rb

# Rails Engine call
`rails plugin new MY_ENGINE --dummy-path=spec/dummy --skip-test-unit --full --database=mysql` 
or `rails plugin new ENGINE_NAME --dummy-path=spec/dummy --skip-test-unit --mountable --database=mysql` 
 
# Configure spec_helper.rb
ENV["RAILS_ENV"] = "test"
require File.expand_path("../dummy/config/environment.rb",  __FILE__)

require 'rspec/rails'

ENGINE_RAILS_ROOT=File.join(File.dirname(__FILE__), '../')

# Requires supporting ruby files with custom matchers and macros, etc,
# in spec/support/ and its subdirectories.
Dir[File.join(ENGINE_RAILS_ROOT, "spec/support/**/*.rb")].each {|f| require f }

RSpec.configure do |config|
  config.use_transactional_fixtures = true

   # Use color in STDOUT
  config.color_enabled = true

  # Use color not only in STDOUT but also in pagers and files
  config.tty = true

  # Use the specified formatter
  config.formatter = :documentation # :progress, :html, :textmate

  config.before(:each) do

  end
  config.after(:each) do

  end
end