rails3 rake does not run my tests

In a fresh R3 app, I seem to be unable to run any 开发者_如何学编程tests (there are 2, the canonical functional test for "/" and another unit test I created)

See this output:

rails_app$ rake test --trace
(in /Users/jan/portfolio/rails_app)
** Invoke test (first_time, not_needed)
rails_app$

What could be wrong? What is the meaning of first_time, not_needed'? t might have to do with the fact, that I am using Mongoid...

When I followed the instructions for Mongoid's installation, I replaced

require 'rails/all'

with

require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"

after learning about (and inserting)

require "rails/test_unit/railtie"

tests started to get picked up