my first spec

rock_paper_scissors.rb

class RockPaperScissors
  attr_reader :result, :choice

  def initialize(choice)

    @choice = choice

    if is_valid_choice?
      @result = play
    else
      @result = instructions
    end

  end

private

  def is_valid_choice?

    if @choice.is_a?(Integer) && (@choice > 0 && @choice < 4)
      @choice = number_to_choice(@choice)
      return true
    elsif @choice.is_a?(String) && ['rock', 'paper', 'scissors'].include?(@choice.downcase)
      @choice = @choice.downcase
      return true
    end

    false
  end

  def play
    @computer_choice = random_choice

    if @choice == @computer_choice
      return "tie!"
    elsif (@choice == "rock" && @computer_choice == "scissors") ||
          (@choice == "paper" && @computer_choice == "rock") ||
          (@choice == "scissors" && @computer_choice == "paper")
      return "won!"
    else
      return "lost!"
    end
  end

  def random_choice
    number_to_choice(Random.new.rand(1...4))
  end

  def instructions
    "please use one of the valid answers below"
  end

  def number_to_choice(number)
    case number
    when 1
      number = "rock"
    when 2
      number = "paper"
    when 3
      number = "scissors"
    end

    return number
  end

end

rock_paper_scissors_spec.rb

require 'rock_paper_scissors'

# game = RockPaperScissors.new('rock')
# game.result => ['win!', 'lose!', 'tie!']
#
# 1 == rock
# 2 == paper
# 3 == scissors

describe "Rock Paper Scissors" do
  let(:answers_snippet) { /valid answers/ }

  context "when a number is passed" do

    it "fails when invalid" do
      game = RockPaperScissors.new(0)
      game.result.should match(answers_snippet)
    end

    it "passes when valid and convert to string value" do
      game = RockPaperScissors.new(1)

      game.result.should_not match(answers_snippet)
      game.choice.should == "rock"
    end
  end

  context "when a string is passed" do

    it "fails when invalid" do
      game = RockPaperScissors.new('cheese')
      game.result.should match(answers_snippet)
    end

    it "passes when valid" do
      game = RockPaperScissors.new('rock')
      game.result.should_not match(answers_snippet)
    end
  end

  it "should tie when rock vs rock" do
    RockPaperScissors.any_instance.stub(:random_choice).and_return('rock')

    game = RockPaperScissors.new('rock')
    game.result.should == "tie!"
  end

  it "rock should beat scissors" do
    RockPaperScissors.any_instance.stub(:random_choice).and_return('scissors')

    game = RockPaperScissors.new('rock')
    game.result.should == "won!"
  end

  it "paper should beat rock" do
    RockPaperScissors.any_instance.stub(:random_choice).and_return('rock')

    game = RockPaperScissors.new('paper')
    game.result.should == "won!"
  end

  it "scissors should beat paper" do
    RockPaperScissors.any_instance.stub(:random_choice).and_return('paper')

    game = RockPaperScissors.new('scissors')
    game.result.should == "won!"
  end

end