How to fake out a subdomain lookup in Rails tests?

I have the following filter defined: ``` # application_controller.rb class ApplicationController < ActionController::Base before_filter :find_account private def find_account @current_account = Account.find_by_subdomain!(request.subdomains.first) end end ``` and in my test: ``` # users_controller_test.rb class UsersControllerTest < ActionController::TestCase setup do @request.host = "test.myapp.local" end # ... end ``` Now `test` is defined as the subdomain for a dummy account that I load prior to all requests using `factory_girl`. However, this is throwing a nil object error, saying that @request is nil. Removing the setup block causes all of my tests to fail as find_account cannot find an account and therefore throws a `RecordNotFound` error. What am I doing wrong?