Por favor, perdone cualquier defecto en esta (mi primera) publicación en StackOverflow. Soy nuevo en Ruby on Rails. Estoy siguiendo elTutorial Rails. He pasado muchas horas sin éxito consultando otros hilos discutiendo el mismo Error de nombre que estoy planteando en esta pregunta.

Cualquier intento mío de ejecutar una prueba rspec así: $ bundle exec rspec spec / models / user_spec.rb produce el error ahora infame: `': Rieles constantes sin inicializar (NameError)

Déjame saber si hay más información que debo proporcionarte para que empiece a rodar.

Aquí está mi gemfile:

source 'https://rubygems.org'  
ruby '2.0.0'  
    #ruby-gemset=railstutorial_rails_4_0  

gem 'rails', '4.0.0'  
gem 'bootstrap-sass', '2.3.2.0'  
gem 'bcrypt-ruby', '3.0.1'  
gem 'faker', '1.1.2'  
gem 'will_paginate', '3.0.4'  
gem 'bootstrap-will_paginate', '0.0.9'  

group :development, :test do
  gem 'sqlite3', '1.3.8'  
  gem 'rspec-rails', '2.13.1'  
  # The following optional lines are part of the advanced setup.  
  # gem 'guard-rspec', '2.5.0'  
  # gem 'spork-rails', '4.0.0'  
  # gem 'guard-spork', '1.5.0'  
  # gem 'childprocess', '0.3.6'  
end  

group :test do  
  gem 'selenium-webdriver', '2.35.1'  
  gem 'capybara', '2.1.0'  
  gem 'factory_girl_rails', '4.2.0'  
  gem 'cucumber-rails', '1.4.0', :require => false  
  gem 'database_cleaner', github: 'bmabey/database_cleaner'  

  # Uncomment these lines on Linux.  
  # gem 'libnotify', '0.8.0'  

  # Uncomment these lines on Windows.  
  # gem 'rb-notifu', '0.0.4'  
  # gem 'win32console', '1.3.2'  
  # gem 'wdm', '0.1.0'  
end  

gem 'sass-rails', '4.0.1'  
gem 'uglifier', '2.1.1'  
gem 'coffee-rails', '4.0.1'  
gem 'jquery-rails', '3.0.4'  
gem 'turbolinks', '1.1.1'  
gem 'jbuilder', '1.0.2'  

group :doc do  
  gem 'sdoc', '0.3.20', require: false  
end  

group :production do  
  gem 'pg', '0.15.1'  
  gem 'rails_12factor', '0.0.2'  
end  

Aquí está mi archivo spec / models / user_spec.rb:

require 'spec_helper'  

describe User do
  pending "add some examples to (or delete) #{__FILE__}"
end

Aquí está mi aplicación / modelos / usuario.rb archivo:
clase Usuario <ActiveRecord :: Base final

Aquí está mi archivo spec_helper.rb:

# This file is copied to spec/ when you run 'rails generate rspec:install'
ENV["RAILS_ENV"] ||= 'test'
Dir[Rails.root.join("spec/support/**/*.rb")].each {|f| require f}

require 'test/unit'
require 'spec_helper'
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 }

# Checks for pending migrations before tests are run.
# If you are not using ActiveRecord, you can remove this line.
ActiveRecord::Migration.check_pending! if defined?(ActiveRecord::Migration)

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

  # 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

  # Run specs in random order to surface order dependencies. If you find an
  # order dependency and want to debug it, you can fix the order by providing
  # the seed, which is printed after each run.
  #     --seed 1234
  config.order = "random"
  config.include Capybara::DSL
end

Definitivamente he ejecutado bundle install. También puedo confirmar que ya he creado la base de datos y ejecutar la migración (ya existe db / test.sqlite3)