FactoryGirl, почему я получаю уже зарегистрированную или неинициализированную константу?

Я пытаюсь провести простой тест для моей модели Курс , я написал эту фабрику:

FactoryGirl.define do
  factory :course do
    name 'How to be happy ?'
    end
end

course_spec.rb:

require "rspec"
require 'factory_girl_rails'
describe "When a course is created" do

  it "can't be deleted if any student is enrolled to it" do
    FactoryGirl.find_definitions
    course = FactoryGirl.build(:course)

    student= Student.create!
    course.students << student
    course.destroy
    course.name.should !=nil
  end
end

но я дохожу до этой строки

course = FactoryGirl.build(:course)

и получаю сообщение об ошибке:

FactoryGirl::DuplicateDefinitionError: Factory already registered: course

если я прокомментирую определение: course на фабрике, я получаю:

NameError: uninitialized constant Course

Есть идеи, пожалуйста?

вот мой Gem Envioronment:

RubyGems Environment:
RUBYGEMS VERSION: 1.8.10
RUBY VERSION: 1.9.3 (2011-10-30 patchlevel 0) [i686-linux]
INSTALLATION DIRECTORY: /home/sam/.rvm/gems/ruby-1.9.3-p0
RUBY EXECUTABLE: /home/sam/.rvm/rubies/ruby-1.9.3-p0/bin/ruby
EXECUTABLE DIRECTORY: /home/sam/.rvm/gems/ruby-1.9.3-p0/bin
RUBYGEMS PLATFORMS:
  ruby
  x86-linux
GEM PATHS:
   /home/sam/.rvm/gems/ruby-1.9.3-p0
   /home/sam/.rvm/gems/ruby-1.9.3-p0@global
GEM CONFIGURATION:
   :update_sources => true
   :verbose => true
   :benchmark => false
   :backtrace => false
   :bulk_threshold => 1000
REMOTE SOURCES:
   http://rubygems.org/
----------------------
IDE: JetBrains RubyMine (EAP) RM-112.291, build #RM-112.291
OS: Linux 3.0.0-12-generic[i386]
Java: 1.6.0_23-b23
RubyMine SDK Environment:
Sdk: RVM: ruby-1.9.3-p0
Sdk Version: ver.1.9.3p0 ( revision 33570) p0
Ruby Interpreter: /home/sam/.rvm/rubies/ruby-1.9.3-p0/bin/ruby
RVM Sdk: yes, gemset:[default]
RVM Home: /home/sam/.rvm
Sdk Language Level: 1.9
Sdk Load Path:
     /home/sam/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1
     /home/sam/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby/1.9.1/i686-linux
     /home/sam/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/site_ruby
     /home/sam/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/vendor_ruby/1.9.1
     /home/sam/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/vendor_ruby/1.9.1/i686-linux
     /home/sam/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/vendor_ruby
     /home/sam/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1
     /home/sam/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/i686-linux
     /home/sam/rubyMine4beta/rubystubs19
Sdk Gem paths: 
     file:///home/sam/.rvm/gems/ruby-1.9.3-p0/bundler/gems
     file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems
     file:///home/sam/.rvm/gems/ruby-1.9.3-p0@global/gems
Gems used for 'hope':
     ffi (1.0.11, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/ffi-1.0.11)
     sass (3.1.12, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/sass-3.1.12)
     coffee-script-source (1.2.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/coffee-script-source-1.2.0)
     mail (2.3.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/mail-2.3.0)
     activesupport (3.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/activesupport-3.1.0)
     i18n (0.6.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/i18n-0.6.0)
     uglifier (1.2.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/uglifier-1.2.1)
     sprockets (2.0.3, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/sprockets-2.0.3)
     foreigner (1.1.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/foreigner-1.1.1)
     treetop (1.4.10, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/treetop-1.4.10)
     haml (3.1.4, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/haml-3.1.4)
     ansi (1.4.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/ansi-1.4.1)
     mime-types (1.17.2, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/mime-types-1.17.2)
     rack (1.3.6, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rack-1.3.6)
     devise (1.5.2, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/devise-1.5.2)
     warden (1.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/warden-1.1.0)
     diff-lcs (1.1.3, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/diff-lcs-1.1.3)
     activeresource (3.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/activeresource-3.1.0)
     sass-rails (3.1.5, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/sass-rails-3.1.5)
     therubyracer (0.9.9, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/therubyracer-0.9.9)
     rspec-expectations (2.7.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rspec-expectations-2.7.0)
     coffee-rails (3.1.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/coffee-rails-3.1.1)
     activemodel (3.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/activemodel-3.1.0)
     simple_form (1.5.2, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/simple_form-1.5.2)
     bundler (1.0.21, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/bundler-1.0.21)
     thor (0.14.6, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/thor-0.14.6)
     activerecord (3.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/activerecord-3.1.0)
     json (1.6.4, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/json-1.6.4)
     coffee-script (2.2.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/coffee-script-2.2.0)
     execjs (1.2.13, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/execjs-1.2.13)
     turn (0.8.3, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/turn-0.8.3)
     rake (0.9.2.2, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rake-0.9.2.2)
     kaminari (0.13.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/kaminari-0.13.0)
     rdoc (3.12, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rdoc-3.12)
     rspec (2.7.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rspec-2.7.0)
     actionpack (3.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/actionpack-3.1.0)
     rspec-rails (2.7.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rspec-rails-2.7.0)
     guard (0.10.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/guard-0.10.0)
     cocoon (1.0.15, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/cocoon-1.0.15)
     libv8 (3.3.10.4, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/libv8-3.3.10.4-x86-linux)
     rspec-core (2.7.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rspec-core-2.7.1)
     jquery-rails (1.0.19, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/jquery-rails-1.0.19)
     rails (3.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rails-3.1.0)
     rack-ssl (1.3.2, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rack-ssl-1.3.2)
     arel (2.2.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/arel-2.2.1)
     erubis (2.7.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/erubis-2.7.0)
     rb-fsevent (0.4.3.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rb-fsevent-0.4.3.1)
     builder (3.0.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/builder-3.0.0)
     orm_adapter (0.0.5, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/orm_adapter-0.0.5)
     rack-cache (1.0.3, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rack-cache-1.0.3)
     multi_json (1.0.4, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/multi_json-1.0.4)
     spork (0.9.0.rc9, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/spork-0.9.0.rc9)
     tilt (1.3.3, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/tilt-1.3.3)
     rack-mount (0.8.3, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rack-mount-0.8.3)
     tzinfo (0.3.31, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/tzinfo-0.3.31)
     validate_url (0.2.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/validate_url-0.2.0)
     sqlite3 (1.3.5, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/sqlite3-1.3.5)
     rspec-mocks (2.7.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rspec-mocks-2.7.0)
     polyglot (0.3.3, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/polyglot-0.3.3)
     railties (3.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/railties-3.1.0)
     hike (1.2.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/hike-1.2.1)
     guard-spork (0.5.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/guard-spork-0.5.0)
     factory_girl_rails (1.4.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/factory_girl_rails-1.4.0)
     factory_girl (2.3.2, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/factory_girl-2.3.2)
     will_paginate (3.0.2, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/will_paginate-3.0.2)
     rack-test (0.6.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/rack-test-0.6.1)
     client_side_validations (3.1.4, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/client_side_validations-3.1.4)
     actionmailer (3.1.0, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/actionmailer-3.1.0)
     bcrypt-ruby (3.0.1, file:///home/sam/.rvm/gems/ruby-1.9.3-p0/gems/bcrypt-ruby-3.0.1)

ИЗМЕНИТЬ

Файл spec_helper.rb:

require 'rubygems'
require 'spork'




    Spork.prefork do
      # Loading more in this block will cause your tests to run faster. However, 
      # if you change any configuration or code from libraries loaded here, you'll
      # need to restart spork for it take effect.
      ENV["RAILS_ENV"] ||= 'test'
      require File.expand_path("../../config/environment", __FILE__)
      require 'rspec/rails'
      require 'rspec/autorun'

      # Requires supporting ruby files with custom matchers and macros, etc,
      # in spec/support/ and its subdirectories.
      Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}

      RSpec.configure do |config|
        # == Mock Framework
        #
        # If you prefer to use mocha, flexmock or RR, uncomment the appropriate line:
        #
        # config.mock_with :mocha
        # config.mock_with :flexmock
        # config.mock_with :rr
        config.mock_with :rspec

        # Remove this line if you're not using ActiveRecord or ActiveRecord fixtures
        config.fixture_path = "#{::Rails.root}/spec/fixtures"

        # If you're not using ActiveRecord, or you'd prefer not to run each of your
        # examples within a transaction, remove the following line or assign false
        # instead of true.
        config.use_transactional_fixtures = true

        # If true, the base class of anonymous controllers will be inferred
        # automatically. This will be the default behavior in future versions of
        # rspec-rails.
        config.infer_base_class_for_anonymous_controllers = false
      end





    end

    Spork.each_run do
      # This code will be run each time you run your specs.
      FactoryGirl.factories.clear
      # either this if you have multiple files under 'spec/factories',
      # or just load the single file, such as 'spec/factories.rb'
      Dir.glob("#{::Rails.root}/spec/factories/*.rb").each do |file|
         load "#{file}"
      end

    end