角にとって右は右斜め上で、上は左斜め上

player.rb

# -*- coding: utf-8 -*-
module Movable
  def position(position=nil)
    return {:x=>@x, :y=>@y} unless position
    
    @x = position[:x] 
    @y = position[:y]
  end

  def set_position_or_player(position)
    position (position.is_a?(Movable) ? position.position : position)
  end

  def set_ratio(x, y)
    @x_ratio = x
    @y_ratio = y
  end

  def move_x(plusMinus)
    @x += 10 * @x_ratio * plusMinus
  end

  def move_y(plusMinus)
    @y += 10 * @y_ratio * plusMinus
  end

  def move(direction)
    case direction
    when :up
      move_y -1
    when :down
      move_y +1
    when :left
      move_x -1
    when :right
      move_x +1
    end
  end
end

class NormalPlayer
  include Movable
  def initialize(position)
    set_position_or_player position
    set_ratio 1, 1
  end
end

class FastPlayer < NormalPlayer
  include Movable
  def initialize(position)
    super
    set_ratio 2, 2
  end
end

class KaniPlayer < NormalPlayer
  include Movable
  def initialize(position)
    super
    set_ratio 4, 0.5
  end
end

class NechigaePlayer < NormalPlayer
  include Movable

  def position(position=nil)
    return {:x=>@y, :y=>@x} unless position
    
    @x = position[:y] 
    @y = position[:x]
  end
end

class KakuPlayer < NormalPlayer
  include Movable

  def move_x(plusMinus)
    @x += 10 * @x_ratio * plusMinus
    @y += 10 * @y_ratio * plusMinus
  end

  def move_y(plusMinus)
    @x -= 10 * @x_ratio * plusMinus
    @y += 10 * @y_ratio * plusMinus
  end
end

player_spec.rb

# -*- coding: utf-8 -*-

$: << File.expand_path(File.dirname(__FILE__))
require 'player'

describe NormalPlayer do
  let (:player) { NormalPlayer.new(x: 100, y: 100) }
  it "通常 モードで正しい動きをすること" do
    player.tap{|p| p.move(:up)    }.position.should == {x: 100, y: 90}
    player.tap{|p| p.move(:left)  }.position.should == {x: 90,  y: 90}
    player.tap{|p| p.move(:down)  }.position.should == {x: 90,  y: 100}
    player.tap{|p| p.move(:right) }.position.should == {x: 100, y: 100}
  end
end

describe FastPlayer do
  let (:player) { FastPlayer.new(x: 100, y: 100) }
  it "倍速 モードで正しい動きをすること" do
    player.tap{|p| p.move(:up)    }.position.should == {x: 100, y: 80}
    player.tap{|p| p.move(:left)  }.position.should == {x: 80,  y: 80}
    player.tap{|p| p.move(:down)  }.position.should == {x: 80,  y: 100}
    player.tap{|p| p.move(:right) }.position.should == {x: 100, y: 100}
  end
end

describe KaniPlayer do
  let (:player) { KaniPlayer.new(x: 100, y: 100) }
  it "カニ モードで正しい動きをすること" do
    player.tap{|p| p.move(:up)    }.position.should == {x: 100, y: 95}
    player.tap{|p| p.move(:left)  }.position.should == {x: 60,  y: 95}
    player.tap{|p| p.move(:down)  }.position.should == {x: 60,  y: 100}
    player.tap{|p| p.move(:right) }.position.should == {x: 100, y: 100}
  end
end

describe NechigaePlayer do
  let (:player) { NechigaePlayer.new(x: 100, y: 100) }
  it "寝違え モードで正しい動きをすること" do
    player.tap{|p| p.move(:up)    }.position.should == {x: 90,  y: 100}
    player.tap{|p| p.move(:left)  }.position.should == {x: 90,  y: 90}
    player.tap{|p| p.move(:down)  }.position.should == {x: 100, y: 90}
    player.tap{|p| p.move(:right) }.position.should == {x: 100,  y: 100}
  end
end

describe KakuPlayer do
  let (:player) { KakuPlayer.new(x: 100, y: 100) }
  it "角 モードで正しい動きをすること" do
    player.tap{|p| p.move(:up)    }.position.should == {x: 110, y: 90}
    player.tap{|p| p.move(:left)  }.position.should == {x: 100, y: 80}
    player.tap{|p| p.move(:down)  }.position.should == {x: 90,  y: 90}
    player.tap{|p| p.move(:right) }.position.should == {x: 100, y: 100}
  end
end

とりあえず実装したけど、どうやってリファクタリングしようかな？

@x += 10 * @x_ratio * plusMinus がいっぱい出てくるのが嫌だなぁ。