rspec and cookies

Hello

can anyone tell me how to test cookies using rspec? specifically, I'd like to be able to set a cookie before a get/post request and also to test the cookies which have been set by a get/post request

I know I can use cookies[:name] = 'value' to set a cookie but how would I set expiry information on such a cookie? when i try to pass a hash {:value => 'value', :expires => 3.days.from_now} the entire hash becomes the value of cookies[:name]

thanks
david