newbie testing: xml_http_request and route, route not recognised

In my view the generated html has this, and it works just fine:

<a href="/people/2/movies/19" method="delete" onclick="if (confirm ('Delete "Highlander". Are you sure?')) { new Ajax.Request('/people/2/ movies/19', {asynchronous:true, evalScripts:true, method:'delete', parameters:'authenticity_token=' + encodeURIComponent ('3a75bac4c7d8a5a2470788e7c428d2b76928aa3c')}); }; return false;">delete</a>

So in my functional tests I tried the following and it tells me the action isn't recognized, as if it isn't translating the :delete method to the destroy action in the controller :

xml_http_request :delete, person_movie_path(movies (:one).person_id,movies(:one).id)

"rake test" gets me :

test_delete(MoviesControllerTest): ActionController::UnknownAction: No action responded to /people/ 520095529/movies/953125641. Actions: create, create_guid , delete_more_than, destroy, edit, edit_person_movie_path, exception, exception=, index, log_for_stats, log_login, new, redirect_loop_or_default, referrer_url, rescue_action_without_handler, save_referrer_to_cookie, store_loop, and update

I'm a bit perplexed. googling didn't get me any clues. The route is correct, I think. See this pastie http://www.pastie.org/372719 if you think my movie routes may be up the spout.

Any ideas? (I hope so)