How to do proper database testing (TDD) on Rails 3 using MongoDB and Mongoid

Question

How would go about writing proper unit testing (and integration testing for that matter) using MongoDB through Mongoid on Rails ?

I am asking, because to the opposite of

Answer 1

Here's what I did (using Test::Unit and Mongoid 3)...

# test/test_helper.rb
setup {
  Mongoid.default_session.collections.select {|c| c.name !~ /system/ }.each(&:drop)
}