cancan with STI

cancanWithSti.rb

begin
  require 'bundler/inline'
rescue LoadError => e
  $stderr.puts 'Bundler version 1.10 or later is required. Please update your Bundler'
  raise e
end

gemfile(true) do
  source 'https://rubygems.org'
  gem 'rails', '5.0.7'  # use correct rails version
  gem 'cancancan' # use correct cancancan version
  gem 'sqlite3' # use another DB if necessary
  gem 'byebug'
end

require 'active_record'
require 'cancancan'
require 'cancan/model_adapters/active_record_adapter'
require 'cancan/model_adapters/active_record_4_adapter'
require 'minitest/autorun'
require 'logger'

# This connection will do for database-independent bug reports.
ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')

ActiveRecord::Base.logger = Logger.new(STDOUT)

# create your tables here
ActiveRecord::Schema.define do
   create_table :users, force: true  do |t|
    t.string :name
  end

  create_table :surveys, force: true  do |t|
    t.integer :user_id
    t.string :type
  end
end

class User < ActiveRecord::Base
end

class Survey < ActiveRecord::Base
end

class Climate < Survey
end

class Evaluation < Survey
end

class Ability
  include CanCan::Ability

  def initialize(user)
    can :index, Survey
    can :destroy, Evaluation
  end
end

class BugTest < Minitest::Test
  def test_can_index_climate_and_evaluation
    Climate.create!
    Evaluation.create!

    ability = Ability.new(User.new)

    climate = Climate.first
    evaluation = Evaluation.first

    assert ability.can? :index, climate
    assert ability.can? :index, evaluation
  end

  def test_can_access_destroyable_surveys
    Climate.create!
    Evaluation.create!

    ability = Ability.new(User.new)

    evaluations = Evaluation.accessible_by(ability, :destroy)
    surveys = Survey.accessible_by(ability, :destroy)

    assert_equal 1, evaluations.length
    assert_equal 1, surveys.length
  end
end