Mars rovers from Slava

rover.rb

class Rover

  MOVE = {
    'N' => lambda{ |position| position[:y] += 1 },
    'E' => lambda{ |position| position[:x] += 1 },
    'S' => lambda{ |position| position[:y] -= 1 },
    'W' => lambda{ |position| position[:x] -= 1 }
  }.freeze

  ROTATE = {
    'R' => lambda{ |directions| directions << directions.shift },
    'L' => lambda{ |directions| directions.unshift directions.pop }
  }.freeze

  def initialize(options = {})
    @directions = %w{ N E S W }
    @plateau, @position, @direction = options[:plateau], options[:position], @directions.index(options[:direction])
  end
  
  def direction
    @directions[@direction]
  end

  def run(commands)
    commands.each_char.map do |action|
      action == 'M' ? MOVE[direction].call(@position) : ROTATE[action].call(@directions)
    end
    [@position[:x], @position[:y], direction]
  end

end

rover_test.rb

require 'rover'
require 'test/unit'

class RoverTest < Test::Unit::TestCase
  
  def test_run
    @rover = Rover.new(:plateau => [5, 5], :position => {:x => 1, :y => 2}, :direction => 'N')
    assert_equal([1, 3, 'N'], @rover.run('LMLMLMLMM'))
  end
  
end

__END__
INPUT AND OUTPUT

Test Input:
5 5
1 2 N
LMLMLMLMM
3 3 E
MM R MM RM RR M

Expected Output:
1 3 N
5 1 E
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