The secret behind Rails Integration Test

Find what is behind Rails Integration Test on good blog's post named HeadlessApp

$ script/console
Loading development environment.

>> app.class
=> ActionController::Integration::Session

>> app.get "/home"
=> 302

>> app.controller.params
=> {"action"=>"home", "controller"=>"accounts"}

>> app.response.redirect_url
=> "http://www.example.com/login"