Got different results from D&D Agile book on test of unit test

$ ruby test/unit/pagespec_test.rb Loaded suite test/unit/pagespec_test Started .E.... Finished in 0.502818 seconds.

  1) Error: testservers(ActionController::TestCase): ArgumentError: wrong number of arguments (0 for 1)     /usr/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/ test_case .rb:48:in `initialize'     /usr/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/ test_case .rb:48:in `new'     /usr/lib/ruby/gems/1.8/gems/actionpack-2.0.2/lib/action_controller/ test_case .rb:48:in `setup_without_fixtures'     /usr/lib/ruby/gems/1.8/gems/activerecord-2.0.2/lib/active_record/ fixtures.rb :979:in `full_setup'     /usr/lib/ruby/gems/1.8/gems/activesupport-2.0.2/lib/active_support/ testing/d efault.rb:7:in `run'

6 tests, 1 assertions, 0 failures, 1 errors ---snip---- This doesn't appear to be pointing to any of my code, but rather to rails itself. Line 48 starts as follows near the end of test_case.rb:

      @controller = self.class.controller_class.new       @request = TestRequest.new       @response = TestResponse.new     end   end end ---snip--- Even if it's me, it would be nice if the diagnostic message were more helpful.