CanCanCan Issue

main.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', '5.1.0'  # use correct rails version
  gem 'cancancan' # use correct cancancan version
  gem 'sqlite3' # use another DB if necessary
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 :books, force: true  do |t|
    t.integer :user_id
  end

  create_table :users, force: true  do |t|
    t.string :name
  end
end

class Book < ActiveRecord::Base
  belongs_to :user
end

class User < ActiveRecord::Base
  has_many :books
end

class Ability
  include CanCan::Ability

  def initialize(user)
    can :read, Book, user: user
  end
end

class BugTest < Minitest::Test
  def test_bug
    user1 = User.create!
    user2 = User.create!
    books = Book.create([{user: user1},{user: user2}])
    ability = Ability.new(user1)
    books = Book.accessible_by(ability, :read).count
    assert_equal 1, books
  end
end