Implementation of Greeting Message application and barewords

barewords.rb

require 'rspec'
require 'forwardable'

RSpec.configure do |config|
  config.mock_with :rspec
  config.color_enabled = true
end

def program_name
  "Greeting Messages"
end

module GreetingMessages
  VERSION = "Version 1"

  def version
    VERSION
  end

  class Error < StandardError
    def initialize(attr)
      super("#{attr.to_s} is not present")
    end
  end
end

class Specialization
  def initialize(subject)
    @subject = subject
  end
  
  def specialization
    "#{@subject} magic"
  end
end

class PairingSession
  include GreetingMessages
  extend ::Forwardable

  SALUTATION = "Hi"

  attr_reader :pair_name
  
  def_delegators :@specialization, :specialization

  def initialize(p_name, sp)
    @pair_name = p_name
    @specialization = Specialization.new(sp)
  end

  def salutation
    SALUTATION
  end

  def greet(person_info = {})
    [:title, :first_name, :last_name].each {|sym| raise Error.new(sym) unless person_info[sym]}
    title = "#{person_info[:title]}"
    name = "#{person_info[:first_name]} #{person_info[:last_name]}"
    "#{salutation} #{title} #{name}, welcome to #{program_name} #{version}. My name is #{pair_name}. Let me show you some #{specialization}."
  end
end

describe "barewords" do
  it "prints a greeting message for Suman Mukherjee" do
    PairingSession.new("James", "Ruby").greet(:title => "Mr", :first_name => "Suman", :last_name => "Mukherjee").should eq("Hi Mr Suman Mukherjee, welcome to Greeting Messages Version 1. My name is James. Let me show you some Ruby magic.")
  end

  it "prints a greeting message for Vicky Farrand" do
    PairingSession.new("Mike", "Javascript").greet(:title => "Miss", :first_name => "Vicky", :last_name => "Farrand").should eq("Hi Miss Vicky Farrand, welcome to Greeting Messages Version 1. My name is Mike. Let me show you some Javascript magic.")
  end

  context "when parameters are not passed" do
    it "raises an error" do
      expect { PairingSession.new("Mike", "Javascript").greet(:first_name => "Vicky", :last_name => "Farrand") }.to raise_exception(GreetingMessages::Error, "title is not present")
      expect { PairingSession.new("Mike", "Javascript").greet(:title => "Miss", :last_name => "Farrand")}.to raise_exception(GreetingMessages::Error, "first_name is not present")
      expect { PairingSession.new("Mike", "Javascript").greet(:title => "Miss", :first_name => "Vicky")}.to  raise_exception(GreetingMessages::Error, "last_name is not present")
    end
  end
end