Can't get absolute urls working in this functional test

I've created a new rails project, and for some reason absolute urls aren't working in my functional test.

I have an AssetsController, and am using map.resources :assets. localhost:3000/assets works fine.

In my functional testing, "get :index" works fine, but anything using absolute urls (get '/assets', get assets_url, get '/assets/index') fails with the following error:

test_index(AssetsControllerTest):
ActionController::UnknownAction: No action responded to http://test.host/assets
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/filters.rb:363:in `perform_action_without_benchmark'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/benchmarking.rb:66:in `perform_action_without_rescue'
     /usr/local/lib/ruby/1.8/benchmark.rb:293:in `measure'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/benchmarking.rb:66:in `perform_action_without_rescue'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/rescue.rb:81:in `perform_action'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/base.rb:410:in `process_without_filters'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/filters.rb:372:in `process_without_session_management_support'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/session_management.rb:114:in `process_without_test'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/test_process.rb:15:in `process'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/test_process.rb:369:in `process'
     /Users/jon/Developer/MillicentAssets/config/../vendor/rails/actionpack/lib/action_controller/test_process.rb:340:in `get'
     test/functional/assets_controller_test.rb:17:in `test_index'

I know this works fine in my other rails apps, but I've been staring at this for 2 hours without getting anywhere. Any suggestions?

Jon

Anyone?