Facebooker talk - Jul 2008 - facebooker rspec

hey,

When converting a test form Karate Poke app to rspec, it doesn''t pass.
The test is:

def test_get_new_requires-user
  facebook_get :new, :fb_sig_user => nil
  assert_facebook_redirect_to Facebooker::Session.create.install_url
end

in rspec I have;

describe InvitationController do

  integrate_views

  describe ''get/new'' do
    it ''requires a user'' do
      facebook_get :new, :fb_sig_user => nil
      assert_facebook_redirect_to Facebooker::Session.create.install_url
    end
  end
end

I run ''rake test'' and get
  Test::Unit::AssertionfailedError in InvitationsController get/new
requires a user
  <nil> expected to not be nil.
.../vendor/plugins/lib/facebooker/rails/test_helpers.rb:6:in
''assert_facebook_redirect_to''

What am I doing wrong? Or how should I write this in rspec?

Thanks,
James