Factory Police: detect unused factories in your tests

factory_police.rb

# spec/spec_helper.rb

config.after(:all, db: true) do
  puts
  puts
  FactoryPolice.report
end

# spec/support/factory_police.rb

module FactoryGirl
  class << self
    alias_method :__create__, :create
    def create(*args)
      FactoryPolice.new __create__(*args)
    end
  end
end

class FactoryPolice < BasicObject
  @@proxies = []
  def self.report
    @@proxies.each(&:report)
  end

  def initialize(model)
    @created_at = caller[3].split(':').take(2).join(':')
    @model = model
    @@proxies << self
  end

  def report
    if useless?
      puts "[ #{@created_at} ] - #{@model} is never interacted with directly"
    end
  end

  def method_missing(m, *args, &block)
    calls[m] += 1
    @model.send m, *args, &block
  end

  private

  def useless?
    (@calls.keys - ignore).empty?
  end

  def ignore
    [:puts, :caller]
  end

  def calls
    @calls ||= ::Hash.new { |h, k| h[k] = 0 }
  end
end