diff --git a/Gemfile b/Gemfile
index 1aa98e4..7e38847 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,2 +1,7 @@
 source "http://rubygems.org"
 gemspec
+
+group :test do
+  gem 'mocha'
+  gem 'flexmock'
+end
diff --git a/Gemfile.lock b/Gemfile.lock
index ae1d0f6..dc45df0 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,6 +11,8 @@ GEM
   specs:
     emk-sinatra-url-for (0.2.1)
       sinatra (>= 0.9.1.1)
+    flexmock (0.9.0)
+    mocha (0.9.12)
     rack (1.3.0)
     rack-test (0.6.0)
       rack (>= 1.0)
@@ -23,5 +25,7 @@ PLATFORMS
   ruby
 
 DEPENDENCIES
+  flexmock
+  mocha
   rack-test (>= 0.3.0)
   sinatra-static-assets!
diff --git a/test/sinatra_static_assets_test.rb b/test/sinatra_static_assets_test.rb
index 60c344f..6afa937 100644
--- a/test/sinatra_static_assets_test.rb
+++ b/test/sinatra_static_assets_test.rb
@@ -1,6 +1,8 @@
 require 'sinatra_app'
 require 'test/unit'
 require 'rack/test'
+require 'flexmock/test_unit'
+require 'mocha'
 
 set :environment, :test
 
@@ -53,5 +55,16 @@ EOD
 <a href="/bar/topr">Tatry Mountains Rescue Team</a>
 EOD
   end
-  
+
+  def test_tags_returns_time_stamp_when_file_exists
+    file_path = "#{Sinatra::Application.root}/public/bar/javascripts/summer.js"
+    File.expects(:"exists?").with(file_path).returns(true)
+    File.expects(:mtime).with(file_path).returns(123456789)
+
+    get '/javascript_script_tag', {}, 'SCRIPT_NAME' => '/bar'
+    assert last_response.ok?
+    assert_equal last_response.body,  <<EOD
+<script charset="iso-8859-2" src="/bar/javascripts/summer.js?123456789" type="text/javascript"></script>
+EOD
+  end
 end