make the unpermitted parameters errors in Ruby on Rails more obvious

Problem

When you are adding new attributes to your model after the initial creation, they are not by default included in the permitted parameters list. Sometimes the error is not so obvious to see when testing, unless you look at the test log files.

Solution

To make the error more obvious, there is the following configuration option that you can set up in config/environments/test.rb (tip taken from Rails 4 In Action):

no such file to load — pdfkit (LoadError)

Problem
You are trying to use the pdfkit (here) in your rails application, and you configure it according to the configuration options for the rails 2.x in the config/environment.rb file. Although the application works, when you are trying to use the console you get the error:

no such file to load -- pdfkit (LoadError)

Solution
Make sure that:

require 'pdfkit'
in the config/environment.rb file comes after the line:

require File.join(File.dirname(__FILE__), 'boot')