ruby
require 'spec_helper'

class Sandwich
  include Mongoid::Document
  embeds_many :slices
end

class Slice
  include Mongoid::Document
  field :position, default: 0
  include Mongoid::Document
  embedded_in :sandwiches
  embeds_one :measure
end

class Measure
  include Mongoid::Document
  field :thickness
  embedded_in :slice
end

describe "relationship" do
  it "uses a positional operator" do
    sandwich = Sandwich.create!
    slice = Slice.new
    sandwich.slices << slice
    Moped.logger = Logger.new(STDOUT)
    Moped.logger.level = Logger::DEBUG
    slice.measure = Measure.new
  end
end

  MOPED: 127.0.0.1:27017 UPDATE 
    database=mongoid_test 
    collection=sandwiches 
    selector={"_id"=>"510af81c3b55524e16000001", "slices._id"=>"510af81c3b55524e16000002"} 
    update={"$set"=>{"slices.0.measure"=>{"_id"=>"510af81c3b55524e16000003"}}} flags=[]