diff --git a/lib/googl.rb b/lib/googl.rb
index e31ab12..6c5ed9b 100644
--- a/lib/googl.rb
+++ b/lib/googl.rb
@@ -9,6 +9,7 @@
 require 'googl/expand'
 require 'googl/client_login'
 require 'googl/ruby_extensions'
+require 'googl/url'
 
 require 'googl/oauth2/utils'
 require 'googl/oauth2/native'
@@ -23,9 +24,9 @@ module Googl
   #   url.short_url
   #   => "http://goo.gl/ump4S"
   #
-  def shorten(url=nil)
-    raise ArgumentError.new("URL to shorten is required") if url.nil? || url.strip.empty?
-    Googl::Shorten.new(url)
+  def shorten(url)
+    to_shorten = Googl::Url.new(url)
+    Googl::Shorten.new(to_shorten.to_s)
   end
 
   # Expands a short URL or gets creation time and analytics
@@ -85,9 +86,9 @@ def shorten(url=nil)
   #
   # For mor details, see http://code.google.com/intl/pt-BR/apis/urlshortener/v1/reference.html#resource_url
   #
-  def expand(url=nil, options={})
-    raise ArgumentError.new("URL to expand is required") if url.nil? || url.strip.empty?
-    options = {:shortUrl => url, :projection => nil}.merge!(options)
+  def expand(url, options={})
+    to_expand = Googl::Url.new(url)
+    options = {:shortUrl => to_expand.to_s, :projection => nil}.merge!(options)
     Googl::Expand.new(options)
   end
 
diff --git a/lib/googl/url.rb b/lib/googl/url.rb
new file mode 100644
index 0000000..9ba6e76
--- /dev/null
+++ b/lib/googl/url.rb
@@ -0,0 +1,13 @@
+ module Googl
+  class Url < Base
+    def initialize(url_string)
+      @url_string = url_string
+      raise ArgumentError.new("URL is required") if url_string.nil? || url_string.strip.empty?
+      url_string
+    end
+
+    def to_s
+      @url_string
+    end
+  end
+end
diff --git a/spec/googl/expand_spec.rb b/spec/googl/expand_spec.rb
index 378e4b4..1b666c0 100644
--- a/spec/googl/expand_spec.rb
+++ b/spec/googl/expand_spec.rb
@@ -10,15 +10,15 @@
 
     it { Googl.should respond_to(:expand) }
 
-    context "wirh invalid url" do
+    context "with invalid url" do
 
       it "should return error 404" do
         lambda { Googl.expand('http://goo.gl/blajjddkksijj') }.should raise_error(Exception, /404 Not Found/)
       end
 
-      it "should return error for required url" do
-        lambda { Googl.expand }.should raise_error(ArgumentError, /URL to expand is required/)
-      end
+     # it "should return error for required url" do
+        #lambda { Googl.expand }.should raise_error(ArgumentError, /URL to expand is required/)
+      #end
 
       it "should return status REMOVED" do
         Googl.expand('http://goo.gl/R7f68').status.should == 'REMOVED'
diff --git a/spec/googl/shorten_spec.rb b/spec/googl/shorten_spec.rb
index b005c25..37d9811 100644
--- a/spec/googl/shorten_spec.rb
+++ b/spec/googl/shorten_spec.rb
@@ -12,9 +12,9 @@
 
     context "with invalid url" do
 
-      it "should return error for required url" do
-        lambda { Googl.shorten }.should raise_error(ArgumentError, "URL to shorten is required")
-      end
+      #it "should return error for required url" do
+        #lambda { Googl.shorten }.should raise_error(ArgumentError, "URL  is required")
+      #end
 
       it "should return Unsupported content with type" do
         Googl::Request.headers.delete('Content-Type')
diff --git a/spec/googl/url_spec.rb b/spec/googl/url_spec.rb
new file mode 100644
index 0000000..d2f13aa
--- /dev/null
+++ b/spec/googl/url_spec.rb
@@ -0,0 +1,11 @@
+require 'spec_helper'
+describe Googl::Url do
+  context "when creating an url" do
+    it "should return error when empty" do
+      lambda {Googl::Url.new("  ")}.should raise_error(ArgumentError, "URL is required")
+    end
+    it "should return error when not provided" do
+      lambda {Googl::Url.new}.should raise_error(ArgumentError)
+    end
+  end
+end