refactor in order to mock xml call from an app

Rakefile

@@ -3,7 +3,7 @@ require 'rubygems'
 require 'rake'
 require 'echoe'
 
-Echoe.new('google_directions', '0.1.2') do |p|
+Echoe.new('google_directions', '0.1.3') do |p|
   p.description    = "Ruby-wrapper for Google Directions API.  Can return the drive time and driving distance between to places"
   p.url            = "http://github.com/joshcrews/Google-Directions-Ruby"
   p.author         = "Josh Crews"

google_directions.gemspec

@@ -2,11 +2,11 @@
 
 Gem::Specification.new do |s|
   s.name = %q{google_directions}
-  s.version = "0.1.2"
+  s.version = "0.1.3"
 
   s.required_rubygems_version = Gem::Requirement.new(">= 1.2") if s.respond_to? :required_rubygems_version=
   s.authors = ["Josh Crews"]
-  s.date = %q{2010-07-15}
+  s.date = %q{2010-07-20}
   s.description = %q{Ruby-wrapper for Google Directions API.  Can return the drive time and driving distance between to places}
   s.email = %q{[email protected]}
   s.extra_rdoc_files = ["README.textile", "lib/google_directions.rb"]

lib/google_directions.rb

@@ -10,21 +10,24 @@ def initialize(location_1, location_2)
     @location_2 = location_2
     options = "origin=#{transcribe(@location_1)}&destination=#{transcribe(@location_2)}"
     @xml_call = @base_url + options
-    @xml = get_url(@xml_call)
     @status = find_status
   end
 
   # an example URL to be generated
   #http://maps.google.com/maps/api/directions/xml?origin=St.+Louis,+MO&destination=Nashville,+TN&sensor=false&key=ABQIAAAAINgf4OmAIbIdWblvypOUhxSQ8yY-fgrep0oj4uKpavE300Q6ExQlxB7SCyrAg2evsxwAsak4D0Liiv
 
   def find_status
-    doc = Nokogiri::XML(@xml)
+    doc = Nokogiri::XML(xml)
     doc.css("status").text
   end
 
-   def xml
-     @xml
-   end
+  def xml
+    unless @xml.nil?
+       @xml
+    else
+      @xml ||= get_url(@xml_call)
+    end
+  end
 
   def xml_call
     @xml_call
@@ -34,7 +37,7 @@ def drive_time_in_minutes
     if @status != "OK"
       drive_time = 0
     else
-      doc = Nokogiri::XML(@xml)
+      doc = Nokogiri::XML(xml)
       drive_time = doc.css("duration value").last.text
       convert_to_minutes(drive_time)
     end
@@ -44,7 +47,7 @@ def distance_in_miles
     if @status != "OK"
       distance_in_miles = 0
     else
-      doc = Nokogiri::XML(@xml)
+      doc = Nokogiri::XML(xml)
       meters = doc.css("distance value").last.text
       distance_in_miles = (meters.to_f / 1610.22).round
       distance_in_miles