Accessing session attributes from an integration test

I have a very simple integration test based off of an example and
Agile Web Development with Rails but I can't seem to get it to work.
I'm simply setting a user id in the session via the get method in the
test but then can't access it when it hits my login controller.

Here is the relevant code in the integration test

Make sure that you are using the right key for the user id. Run rake
db:sessions:clear, restart your server and try again.

I had to change

get :index, {}, { :user_id => users(:bart).id }

to

get :index, {}, { 'user_id' => users(:bart).id }

The book example uses the original symbol version.