Question

I’ve refactored part of my test suite to not load rails when performing tests. The code below is an example of a test file that loads only selection pieces of Rails. It also fakes the “project” class. My problem is that this faked project class ends up overriding the normal project class and all other tests that involve the project class now fail.

How do I un-override my project class after this test file runs?

require 'active_model'
require 'active_model/validations'
require 'active_record/callbacks'
require 'active_support/core_ext/string'
class Project
  include ActiveModel::Validations    
  include ActiveRecord::Callbacks
  def initialize(attributes = {})
    @general_media = attributes[:general_media]
  end
  attr_accessor :general_media
end

require_relative '../../../app/models/project/media.rb'

UPDATE: I think this comes close to what I need, except that I’m getting an error about Project being an uninitialized constant. I must be instantiating this test class incorrectly.

require 'active_model'
require 'active_model/validations'
require 'active_record/callbacks'
require 'active_support/core_ext/string' #used for '.blank?' method

require_relative '../../../app/models/project/media.rb'

describe Project::Media do
  before(:all) do 

    class Project
      include ActiveModel::Validations    
      include ActiveRecord::Callbacks
      def initialize(attributes = {})
        @general_media = attributes[:general_media]
      end
      attr_accessor :general_media
    end

  end

  after(:all) { Object.send(:remove_const, :Project) }

  #then all the tests

Answer 1

You should be able to un-define a class with Module#remove_const.

Object.send(:remove_const, :Project)

Its a private method so you’ll need to use send rather than a regular method call.

UPDATE:

Perhaps try the following:

require 'active_model'
require 'active_model/validations'
require 'active_record/callbacks'
require 'active_support/core_ext/string' #used for '.blank?' method

class Project
  include ActiveModel::Validations    
  include ActiveRecord::Callbacks
  def initialize(attributes = {})
    @general_media = attributes[:general_media]
  end
  attr_accessor :general_media
end

require_relative '../../../app/models/project/media.rb'

describe Project::Media do

  after(:all) { Object.send(:remove_const, :Project) }

  ...

You will need to declare the Project class before the describe block if the subject depends on it. Also assuming your Media model depends on it before you require that.

Later tests for the Project class will need to reload it, assuming they are separate tests you can just require your project model class in that test file if you want a minimal (fast) test, or via the normal spec_helper if you want to load the whole Rails application (slow).

As discussed in comments it might be easier to simply stub out the Project class rather than redefine it.