Factory Bot Benchmark

factory_bot_benchmark.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"
  gem "sqlite3"
  gem "factory_bot"
end

require "active_record"
require "logger"
require "factory_bot"
require 'benchmark'

ActiveRecord::Base.establish_connection(adapter: "sqlite3", database: ":memory:")

ActiveRecord::Schema.define do
  create_table :users, force: true do |t|
  end

  create_table :posts, force: true do |t|
    t.integer :user_id
  end
end

class User < ActiveRecord::Base
  has_many :posts
end

class Post < ActiveRecord::Base
  belongs_to :user
end

FactoryBot.define do
  factory :user do
  end

  factory :post do
    user
  end
end

TIMES = 2000

puts "With no associations:"
Benchmark.bmbm do |bm|
  bm.report("new")            { TIMES.times { User.new } }
  bm.report("build")          { TIMES.times { FactoryBot.build(:user) } }
  bm.report("build_stubbed")  { TIMES.times { FactoryBot.build_stubbed(:user) } }
  bm.report("attributes_for") { TIMES.times { FactoryBot.attributes_for(:user) } }
  bm.report("create")         { TIMES.times { FactoryBot.create(:user) } }
end

puts "\n###########################################################\n\n"

puts 'With one association:'
Benchmark.bmbm do |bm|
  bm.report("new")            { TIMES.times { Post.new } }
  bm.report("attributes_for") { TIMES.times { FactoryBot.attributes_for(:post) } }
  bm.report("build_stubbed")  { TIMES.times { FactoryBot.build_stubbed(:post) } }
  bm.report("build")          { TIMES.times { FactoryBot.build(:post) } }
  bm.report("create")         { TIMES.times { FactoryBot.create(:post) } }
end

puts "\n###########################################################\n\n"

puts 'With one association using parent strategy:'
FactoryBot.use_parent_strategy = true
Benchmark.bmbm do |bm|
  bm.report("new")            { TIMES.times { Post.new } }
  bm.report("attributes_for") { TIMES.times { FactoryBot.attributes_for(:post) } }
  bm.report("build")          { TIMES.times { FactoryBot.build(:post) } }
  bm.report("build_stubbed")  { TIMES.times { FactoryBot.build_stubbed(:post) } }
  bm.report("create")         { TIMES.times { FactoryBot.create(:post) } }
end

=begin
With no associations:
Rehearsal --------------------------------------------------
new              0.018025   0.000013   0.018038 (  0.018047)
build            0.135542   0.000384   0.135926 (  0.136007)
build_stubbed    0.257159   0.002513   0.259672 (  0.259871)
attributes_for   0.284504   0.005921   0.290425 (  0.290730)
create           0.632074   0.004213   0.636287 (  0.643327)
----------------------------------------- total: 1.340348sec

                     user     system      total        real
new              0.017522   0.000055   0.017577 (  0.017611)
build            0.093808   0.000660   0.094468 (  0.095229)
build_stubbed    0.207590   0.000903   0.208493 (  0.209350)
attributes_for   0.219949   0.001365   0.221314 (  0.222297)
create           0.599802   0.002649   0.602451 (  0.604623)

###########################################################

With one association:
Rehearsal --------------------------------------------------
new              0.019851   0.000089   0.019940 (  0.020124)
attributes_for   0.286370   0.001803   0.288173 (  0.289053)
build_stubbed    0.577320   0.005476   0.582796 (  0.586311)
build            0.877632   0.004104   0.881736 (  0.884276)
create           1.552896   0.004795   1.557691 (  1.559153)
----------------------------------------- total: 3.330336sec

                     user     system      total        real
new              0.020835   0.000026   0.020861 (  0.020866)
attributes_for   0.222913   0.001709   0.224622 (  0.224888)
build_stubbed    0.501088   0.003089   0.504177 (  0.504612)
build            0.789108   0.002804   0.791912 (  0.792456)
create           1.478119   0.003536   1.481655 (  1.483404)

###########################################################

With one association using parent strategy:
Rehearsal --------------------------------------------------
new              0.019415   0.000020   0.019435 (  0.019442)
attributes_for   0.298382   0.003267   0.301649 (  0.301948)
build            0.286925   0.001244   0.288169 (  0.288437)
build_stubbed    0.552910   0.002654   0.555564 (  0.556511)
create           1.493076   0.003569   1.496645 (  1.497386)
----------------------------------------- total: 2.661462sec

                     user     system      total        real
new              0.020740   0.000106   0.020846 (  0.020885)
attributes_for   0.225570   0.001421   0.226991 (  0.227156)
build            0.253338   0.000944   0.254282 (  0.254623)
build_stubbed    0.523369   0.002687   0.526056 (  0.526744)
create           1.466646   0.004365   1.471011 (  1.472622)
=end