Por favor, perdoe quaisquer deficiências nesta (minha primeira vez) post no StackOverflow. Eu sou novo em Ruby on Rails. Estou seguindo oTutorial de Rails. Eu passei muitas horas sem sucesso consultando outros tópicos discutindo o mesmo erro de nome que estou levantando nesta questão.

Qualquer tentativa minha de executar um teste rspec da seguinte forma: $ bundle exec rspec spec / models / user_spec.rb gera o erro agora infame: `': constante não inicializada Rails (NameError)

Deixe-me saber se há mais alguma informação que eu deveria fornecer a você para dar o pontapé inicial.

Aqui está o meu 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  

Aqui está o meu arquivo spec / models / user_spec.rb:

require 'spec_helper'  

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

Aqui está o meu arquivo app / models / user.rb:
classe User <ActiveRecord :: Base end

Aqui está o meu arquivo 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

Eu definitivamente executei a instalação do pacote. Eu também posso confirmar que eu já criei o banco de dados e executei a migração (db / test.sqlite3 já existe)