Create missing spec files for a ruby gem

gistfile1.rb

require 'active_support/all'
require 'fileutils'
require 'pathname'

root        = Pathname.pwd
code_folder = root.join('lib')
spec_folder = root.join('spec')

code  = Dir[code_folder.join('**/*.rb')].map { |file| file[(code_folder.to_s.length+1)..-('.rb'.length+1)] }
specs = Dir[spec_folder.join('**/*_spec.rb')].map { |file| file[(spec_folder.to_s.length+1)..-('_spec.rb'.length+1)] }

(code - specs).each do |file|
  klass     = file.camelize
  spec_file = spec_folder.join("#{file}_spec.rb")
  FileUtils.mkdir_p(spec_file.dirname)
  File.open(spec_file, 'w') do |f|
    f.puts <<-END_OF_RUBY.strip_heredoc
      require 'spec_helper'

      describe #{klass} do
        # please don't delete this file because it ensures that
        # this class/module is taken into account for code coverage
        #
        # or even better proposal: please write specs :)
      end
    END_OF_RUBY
  end
  puts "created: #{spec_file}"
end

puts 'DONE all missing spec files created'