Benchmark some simple factories with factory_girl

benchmark.rb

require "rubygems"

gem 'activerecord', "3.0.7"
gem 'sqlite3',      "1.3.3"
gem "factory_girl", "1.3.3"

require "active_record"
require "factory_girl"
require "benchmark"

ActiveRecord::Base.establish_connection(
  :adapter  => 'sqlite3',
  :database => 'test.db'
)

class CreateSchema < ActiveRecord::Migration
  def self.up
    create_table "posts", :force => true do |t|
      t.string   "title"
      t.text     "body"
      t.integer  "user_id"
      t.datetime "created_at"
      t.datetime "updated_at"
    end

    create_table "users", :force => true do |t|
      t.string   "name"
      t.string   "email"
      t.integer  "age"
      t.datetime "created_at"
      t.datetime "updated_at"
    end
  end
end

CreateSchema.suppress_messages { CreateSchema.migrate(:up) }

class User < ActiveRecord::Base
  validates_presence_of :email, :name, :age
  has_many :posts
end

class Post < ActiveRecord::Base
  validates_presence_of :title, :body, :user_id
  belongs_to :user
end

Factory.define :user do |factory|
  factory.name "Bill"
  factory.email "bill@example.com"
  factory.age 26
end

Factory.define :post do |factory|
  factory.title "Hello"
  factory.body "What's up"
  factory.association :user
end

ITERATIONS = 1000

Post.delete_all
User.delete_all

Benchmark.bmbm do |x|
  x.report("Post.new") do
    ITERATIONS.times do
      user = User.new
      user.name = "Bill"
      user.email = "bill@example.com"
      user.age = 26
      post = Post.new
      post.title = "Hello"
      post.body = "What's up"
      post.user = user
    end
  end

  x.report("Factory.build(:post)") do
    ITERATIONS.times do
      user = Factory.build(:user)
      Factory.build(:post, :user => user)
    end
  end

  x.report("Post.new with save!") do
    ITERATIONS.times do
      user = User.new
      user.name = "Bill"
      user.email = "bill@example.com"
      user.age = 26
      user.save!
      post = Post.new
      post.title = "Hello"
      post.body = "What's up"
      post.user = user
      post.save!
    end
    Post.delete_all
    User.delete_all
  end

  x.report("Factory.create(:post)") do
    ITERATIONS.times do
      user = Factory.create(:user)
      Factory.create(:post, :user => user)
    end
    Post.delete_all
    User.delete_all
  end
end

Results

Rehearsal ---------------------------------------------------------
Post.new                0.210000   0.010000   0.220000 (  0.220546)
Factory.build(:post)    0.280000   0.000000   0.280000 (  0.278631)
Post.new with save!     3.620000   1.180000   4.800000 (  6.884482)
Factory.create(:post)   3.710000   1.200000   4.910000 (  6.995768)
----------------------------------------------- total: 10.210000sec

                            user     system      total        real
Post.new                0.180000   0.000000   0.180000 (  0.178181)
Factory.build(:post)    0.230000   0.000000   0.230000 (  0.235513)
Post.new with save!     3.580000   1.190000   4.770000 (  6.832289)
Factory.create(:post)   3.730000   1.180000   4.910000 (  7.073387)