Rock Paper Scissors Black Bytes blog version

rps-blackbytes.rb

module BlackBytesExample
  class Game
    def self.play(move1, move2)
      return :tie if move1.class == move2.class
 
      move2.wins_against?(move1)
    end
  end

  class Rock
    def wins_against?(other_move)
      other_move.do_you_beat_rock?
    end
   
    def do_you_beat_paper?
      false
    end
   
    def do_you_beat_scissors?
      true
    end
  end

  class Paper
    def wins_against?(other_move)
      other_move.do_you_beat_paper?
    end
   
    def do_you_beat_rock?
      true
    end
   
    def do_you_beat_scissors?
      false
    end
  end

  class Scissors
    def wins_against?(other_move)
      other_move.do_you_beat_scissors?
    end
   
    def do_you_beat_paper?
      true
    end
   
    def do_you_beat_rock?
      false
    end
  end
end

include BlackBytesExample
require "minitest/autorun"
describe "Rock Paper Scissors Game" do
  describe "Rock" do
    it "Ties against Rock" do
      assert_equal :tie, Game.play(Rock.new, Rock.new)
    end
    it "Loses against Paper" do
      refute Game.play(Rock.new, Paper.new)
    end
    it " Wins against Scissors" do
      assert Game.play(Rock.new, Scissors.new)
    end
  end

  describe "Paper" do
    it "Wins against Rock" do
      assert Game.play(Paper.new, Rock.new)
    end
    it "Ties against Paper" do
      assert_equal :tie, Game.play(Paper.new, Paper.new)
    end
    it "Loses against Scissors" do
      refute Game.play(Paper.new, Scissors.new)
    end
  end

  describe "Scirssors" do
    it "Loses against Rock" do
      refute Game.play(Scissors.new, Rock.new)
    end
    it "Wins against Paper" do
      assert Game.play(Scissors.new, Paper.new)
    end
    it "Ties against Scissors" do
      assert_equal :tie, Game.play(Scissors.new, Scissors.new)
    end
  end
end

require "benchmark/ips"
Benchmark.ips do |x|
  x.report("BlackBytesExample") do
    Game.play(Rock.new, Rock.new)
    Game.play(Rock.new, Paper.new)
    Game.play(Rock.new, Scissors.new)

    Game.play(Paper.new, Rock.new)
    Game.play(Paper.new, Paper.new)
    Game.play(Paper.new, Scissors.new)

    Game.play(Scissors.new, Rock.new)
    Game.play(Scissors.new, Paper.new)
    Game.play(Scissors.new, Scissors.new)
  end
end

Results

Warming up --------------------------------------
   BlackBytesExample    14.104k i/100ms
Calculating -------------------------------------
   BlackBytesExample    155.594k (± 5.6%) i/s -    775.720k in   5.003031s
Run options: --seed 31728

# Running:

.........

Finished in 0.002388s, 3768.2667 runs/s, 3768.2667 assertions/s.

9 runs, 9 assertions, 0 failures, 0 errors, 0 skips