adding distance_of ability - closes ryanb#21

Author: ryanb

lib/ruby_warrior.rb

@@ -36,7 +36,7 @@
 require 'ruby_warrior/abilities/shoot'
 require 'ruby_warrior/abilities/rescue'
 require 'ruby_warrior/abilities/pivot'
-require 'ruby_warrior/abilities/distance'
+require 'ruby_warrior/abilities/distance_of'
 require 'ruby_warrior/abilities/bind'
 require 'ruby_warrior/abilities/listen'
 require 'ruby_warrior/abilities/direction_of_stairs'

lib/ruby_warrior/abilities/distance.rb

@@ -0,0 +1,13 @@
+module RubyWarrior
+  module Abilities
+    class DistanceOf < Base
+      def description
+        "Pass a Space as an argument, and it will return an integer representing the distance to that space."
+      end
+      
+      def perform(space)
+        @unit.position.distance_of(space)
+      end
+    end
+  end
+end

lib/ruby_warrior/abilities/distance_of.rb

@@ -38,8 +38,12 @@ def move(forward, right = 0)
     end
 
     def distance_from_stairs
-      stairs_x, stairs_y = *@floor.stairs_location
-      (@x - stairs_x).abs + (@y - stairs_y).abs
+      distance_of(@floor.stairs_space)
+    end
+    
+    def distance_of(space)
+      x, y = *space.location
+      (@x - x).abs + (@y - y).abs
     end
 
     def relative_direction_of_stairs

lib/ruby_warrior/position.rb

@@ -0,0 +1,13 @@
+require File.dirname(__FILE__) + '/../../spec_helper'
+
+describe RubyWarrior::Abilities::DistanceOf do
+  before(:each) do
+    @position = stub
+    @distance = RubyWarrior::Abilities::DistanceOf.new(stub(:position => @position, :say => nil))
+  end
+  
+  it "should return distance from stairs" do
+    @position.stubs(:distance_of).with(:space).returns(5)
+    @distance.perform(:space).should == 5
+  end
+end

spec/ruby_warrior/abilities/distance_of_spec.rb

@@ -100,4 +100,9 @@
   it "should return a space at the same location as position" do
     @position.space.location.should == [1, 2]
   end
+  
+  it "should return distance of given space" do
+    @position.distance_of(@floor.space(5, 3)).should == 5
+    @position.distance_of(@floor.space(4, 2)).should == 3
+  end
 end