yaml_file.rb

require 'yaml'

module Serverspec
  module Type

    class YAMLFile < Base
      include RSpec::Expectations

      def initialize(path)
        yaml = YAML.load_file(path)
        return unless yaml

        yaml.each { |key, value| self.send('#{key}=', value) }
      end

      def method_missing(m, *args, &block)
        # fail here with message
        self.fail_with('The key does not exist in the YAML file')
      end
    end

    def yaml_file(path)
      YAMLFile.new(path)
    end
  end
end

include Serverspec::Type