Tests for counter_cache when option is not given

counter_cache_tests

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)

ActiveRecord::Schema.define do
  create_table :posts do |t| 
    t.integer :comments_count, default: 0
  end

  create_table :comments do |t| 
    t.integer :post_id
  end
end

class Post < ActiveRecord::Base
  # No counter_cache
  has_many :comments
end

class Comment < ActiveRecord::Base
  belongs_to :post
end

class BugTest < Minitest::Test
  def test_counter_cache_assuming_option_is_required
    post = Post.create!
    post.comments << Comment.create!

    # comments_count is not incremented, because counter_cache option was not given
    assert_equal 0, post.comments_count

    post.comments.destroy_all

    # comments_count should not be decremented, because counter_cache option was not given
    assert_equal 0, post.comments_count
  end

  def test_counter_cache_works_assuming_option_is_not_required
    post = Post.create!
    post.comments << Comment.create!

    # comments_count should be incremented, because a comments_count column is present
    assert_equal 1, post.comments_count
  end
end