Testing friendly forwarding


In chapter 10 of the rails tutorial there is an exercise to test that friendly forwarding has been enabled:

this is the exercise in question :
Write a test to make sure that friendly forwarding only forwards to the given URL the first time. On subsequent login attempts, the forwarding URL should revert to the default (i.e., the profile page). Hint: Add to the test in Listing 10.29 by checking for the right value of session[:forwarding_url].

I’m completely lost as to how to do this. Does anyone have any ideas? Specifically how can I check for the right value of session[:forwarding_url]?