Recommend Rack::Test in README / note Sinatra::Test deprecation

README.rdoc

@@ -437,34 +437,38 @@ typically don't have to +use+ them explicitly.
 
 == Testing
 
-The Sinatra::Test mixin and Sinatra::TestHarness class include a variety of
-helper methods for testing your Sinatra app:
+Sinatra tests can be written using any Rack-based testing library
+or framework. {Rack::Test}[http://gitrdoc.com/brynary/rack-test] is
+recommended:
 
   require 'my_sinatra_app'
-  require 'test/unit'
-  require 'sinatra/test'
+  require 'rack/test'
 
   class MyAppTest < Test::Unit::TestCase
-    include Sinatra::Test
+    include Rack::Test::Methods
+
+    def app
+      Sinatra::Application
+    end
 
     def test_my_default
       get '/'
-      assert_equal 'Hello World!', @response.body
+      assert_equal 'Hello World!', last_response.body
     end
 
     def test_with_params
-      get '/meet', {:name => 'Frank'}
-      assert_equal 'Hello Frank!', @response.body
+      get '/meet', :name => 'Frank'
+      assert_equal 'Hello Frank!', last_response.body
     end
 
     def test_with_rack_env
-      get '/', {}, :agent => 'Songbird'
-      assert_equal "You're using Songbird!", @response.body
+      get '/', {}, 'HTTP_USER_AGENT' => 'Songbird'
+      assert_equal "You're using Songbird!", last_response.body
     end
   end
 
-See http://www.sinatrarb.com/testing.html for more on Sinatra::Test and using it
-with other test frameworks such as RSpec, Bacon, and test/spec.
+NOTE: The built-in Sinatra::Test module and Sinatra::TestHarness class
+are deprecated as of the 0.9.2 release.
 
 == Command line