Error on 10.1.3 "User/Micropost associations" - ruby-on-rails

Question

I'm fairly new to Ruby on Rails and making my way through Michael Hartl's Rails Tutorial. I've hit a bug I can't seem to fix on Chapter 10 (specifically, 10.1.3 "User/Micropost associations"). The error I run into is when I execute the following rspec command:
$ bundle exec rspec spec/models
It raises the following error:
Failures:
1) Micropost accessible attributes should not allow access to user_id
←[31mFailure/Error:←[0m ←[31mexpect do←[0m
←[31mexpected ActiveModel::MassAssignmentSecurity::Error but nothing was
raised←[0m
←[36m # ./spec/models/micropost_spec.rb:28:in `block (3 levels) in <top (req
uired)>'←[0m
Finished in 5.79 seconds
←[31m27 examples, 1 failure←[0m
Failed examples:
←[31mrspec ./spec/models/micropost_spec.rb:27←[0m ←[36m# Micropost accessible at
tributes should not allow access to user_id←[0m
This is the code for micropost_spec.rb:
require 'spec_helper'
describe Micropost do
let(:user) { FactoryGirl.create(:user) }
before { #micropost = user.microposts.build(content: "Lorem ipsum") }
subject { #micropost }
it { should respond_to(:content) }
it { should respond_to(:user_id) }
it { should respond_to(:user) }
its(:user) { should == user }
it { should be_valid }
describe "when user_id is not present" do
before { #micropost.user_id = nil }
it { should_not be_valid }
end
describe "accessible attributes" do
it "should not allow access to user_id" do
expect do
Micropost.new(user_id: user.id)
end.to raise_error(ActiveModel::MassAssignmentSecurity::Error)
end
end
end
application.rb:
require File.expand_path('../boot', __FILE__)
# Pick the frameworks you want:
require "active_record/railtie"
require "action_controller/railtie"
require "action_mailer/railtie"
require "active_resource/railtie"
require "sprockets/railtie"
# require "rails/test_unit/railtie"
if defined?(Bundler)
# If you precompile assets before deploying to production, use this line
Bundler.require(*Rails.groups(:assets => %w(development test)))
# If you want your assets lazily compiled in production, use this line
# Bundler.require(:default, :assets, Rails.env)
end
module SampleApp
class Application < Rails::Application
# Settings in config/environments/* take precedence over those specified here.
# Application configuration should go into files in config/initializers
# -- all .rb files in that directory are automatically loaded.
config.active_record.whitelist_attributes = true
# Custom directories with classes and modules you want to be autoloadable.
# config.autoload_paths += %W(#{config.root}/extras)
# Only load the plugins named here, in the order given (default is alphabetical).
# :all can be used as a placeholder for all plugins not explicitly named.
# config.plugins = [ :exception_notification, :ssl_requirement, :all ]
# Activate observers that should always be running.
# config.active_record.observers = :cacher, :garbage_collector, :forum_observer
# Set Time.zone default to the specified zone and make Active Record auto-convert to this zone.
# Run "rake -D time" for a list of tasks for finding time zone names. Default is UTC.
# config.time_zone = 'Central Time (US & Canada)'
# The default locale is :en and all translations from config/locales/*.rb,yml are auto loaded.
# config.i18n.load_path += Dir[Rails.root.join('my', 'locales', '*.{rb,yml}').to_s]
# config.i18n.default_locale = :de
# Configure the default encoding used in templates for Ruby 1.9.
config.encoding = "utf-8"
# Configure sensitive parameters which will be filtered from the log file.
config.filter_parameters += [:password]
# Enable the asset pipeline
config.assets.enabled = true
# Version of your assets, change this if you want to expire all your assets
config.assets.version = '1.0'
end
end
micropost.rb...
class Micropost < ActiveRecord::Base
attr_accessible :content
belongs_to :user
validates :user_id, presence: true
end
Thanks in advance for your help!
Thai

Answer 1

So expected ActiveModel::MassAssignmentSecurity::Error but nothing was
raised when Micropost.new(user_id: user.id) is called.
For it to work correctly:
The Rails application should be configured to explicitly whitelist or blacklist accessible parameters; in rails versions before 3.2.3 this was on by default; in previous versions, it has to be done by the following line in config/application.rb as detailed in Listing 10.6 of RailsTutorial book:
config.active_record.whitelist_attributes = true
There shouldn't be a attr_accessible :user_id in the micropost.rb model file.

Answer 2

Try adding
config.active_record.mass_assignment_sanitizer = :strict
To your application.rb file, what I found out is that if not strict, it would just throw a Warning but not an exception.

Answer 3

Like you, I tried all of the solutions above with no luck. I also notice that Hartl's more recent editions of the book for Rails 4 do not contain those tests, so I suspect this approach to testing accessibility does not work in later versions. Perhaps an expert (someone who isn't running through the Rails Tutorial) can chime in.
But.... I noticed this response in another StackOverflow thread recommending the "shoulda-matchers" Gem to test it, and that solved the problem for me (https://stackoverflow.com/a/11876425/3899955). In investigating that Gem, I find it is a nice way to produce readable tests for a number of common ActiveModel, ActiveRecord, and ActionController tests. I am happy to be adding that to my quiver, perhaps you will be too.
I don't take credit for that answer, just wanted to post this so if anyone else is running in to this frustration doing Chapter 10.5, or completing exercise 6 in Chapter 9.