RSpec/Mongoid inheritance of defaults completely different result in test/development - ruby-on-rails

Question

This is one of those ones that makes you think you're going insane...
I have a class Section, and a DraftSection that inherits from it:
(Trimmed for brevity)
class Section
include Mongoid::Document
belongs_to :site
field :name, type: String
end
And
class DraftSection < Section
field :name, type: String, default: "New Section"
end
All simple stuff... console proves (again, trimmed for brevity):
004 > site = Site.first
=> #<Site _id: initech, name: "INITECH">
005 > site.sections.build
=> #<Section _id: 1, site_id: "initech", name: nil>
006 > site.draft_sections.build
=> #<DraftSection _id: 2, site_id: "initech", name: "New Section">
As you can see - the draft section name correctly defaults to "New Section" as it is overridden in the subclass.
Now when I run this spec:
describe "#new" do
it "should return a draft section" do
get 'new', site_id: site.id, format: :json
assigns(:section).should == "Something..."
end
end
Which tests this controller method:
def new
#section = #site.draft_sections.build
respond_with #section
end
Which fails (as expected), but with this:
Failure/Error: assigns(:section).should == "Something..."
expected: "Something..."
got: #<DraftSection _id: 1, site_id: "site-name-4", name: nil> (using ==)
What gives???
Update:
I figured it might be an issue with the different environment settings, so I looked at the mongoid.yml config file and saw this in the options:
# Preload all models in development, needed when models use
# inheritance. (default: false)
preload_models: true
I added it to the test environment settings too, but still no joy :(
Update 2 - the plot thickens...
Thought I'd try loading up the console in the test environment and trying the same as before:
001 > site = Site.first
=> #<Site _id: initech, name: "INITECH">
002 > site.draft_sections.build
=> #<DraftSection _id: 1, site_id: "initech", name: "New Section">
WTF?

Answer 1

Ok, no one's listening, but I'll post the solution here for future reference anyway...
For some reason, some time ago I had a debug session that meant I had left this code in my Spork.each_run block
# Reload all model files when run each spec
# otherwise there might be out-of-date testing
# require 'rspec/rails'
Dir["#{Rails.root}/app/controllers//*.rb"].each do |controller|
load controller
end
Dir["#{Rails.root}/app/models//*.rb"].each do |model|
load model
end
Dir["#{Rails.root}/lib//*.rb"].each do |klass|
load klass
end
This was causing the models to get reloaded on each run of a spec. Not surprisingly, this screwed up the way the classes were set up in memory whilst the specs were running.
Definitely explains why it was such a hard one to debug...
So for future googlers with similar inheritance problems in Rspec only - make sure that there's nothing reloading models anywhere in the test stack.