Make benchmarks run on multiple branches without conflicts

- copy target files to a temp directory
- benchmark cache/no cache on each branch
- compare branches
- remove rake dependency that loads unnecessary files
  - run with ./bin/bench
- remove git gem dependency

Master looks slower than some older refs; need to confirm

Gemfile

@@ -46,5 +46,4 @@ end
 
 group :development, :test do
   gem 'rubocop', '~> 0.34.0', require: false
-  gem 'git'
 end

Rakefile

@@ -48,38 +48,3 @@ task default: [:test, :rubocop]
 
 desc 'CI test task'
 task :ci => [:default]
-
-require 'git'
-require 'benchmark'
-Rake::TestTask.new :benchmark_tests do |t|
-  t.libs << "test"
-  t.test_files = FileList['test/**/*_benchmark.rb']
-  t.ruby_opts = ['-r./test/test_helper.rb']
-  t.verbose = true
-end
-
-task :benchmark do
-  @git = Git.init('.')
-  ref  = @git.current_branch
-
-  actual = run_benchmark_spec ref
-  master = run_benchmark_spec 'master'
-
-  @git.checkout(ref)
-
-  puts "\n\nResults ============================\n"
-  puts "------------------------------------~> (Branch) MASTER"
-  puts master
-  puts "------------------------------------\n\n"
-
-  puts "------------------------------------~> (Actual Branch) #{ref}"
-  puts actual
-  puts "------------------------------------"
-end
-
-def run_benchmark_spec(ref)
-  @git.checkout(ref)
-  response = Benchmark.realtime { Rake::Task['benchmark_tests'].invoke }
-  Rake::Task['benchmark_tests'].reenable
-  response
-end

active_model_serializers.gemspec

@@ -17,6 +17,7 @@ Gem::Specification.new do |spec|
   spec.files         = `git ls-files -z`.split("\x0")
   spec.test_files    = spec.files.grep(%r{^(test|spec|features)/})
   spec.require_paths = ['lib']
+  spec.executables   = []
 
   spec.required_ruby_version = '>= 2.0.0'
 

bin/bench

@@ -0,0 +1,81 @@
+#!/usr/bin/env ruby
+require 'fileutils'
+require 'benchmark'
+require 'pathname'
+require 'shellwords'
+
+ROOT = Pathname File.expand_path(['..', '..'].join(File::Separator), __FILE__)
+TMP_DIR = File.join(ROOT, 'tmp/bench')
+
+def temp_dir_empty?
+  Dir[File.join(TMP_DIR, '*')].none?
+end
+
+def empty_temp_dir
+  FileUtils.mkdir_p(TMP_DIR)
+  Dir[File.join(TMP_DIR, '*')].each do |file|
+    FileUtils.rm(file)
+  end
+end
+
+def fill_temp_dir
+  Dir[File.join(ROOT, 'test', '**', '*_benchmark.rb')].each do |file|
+    FileUtils.cp(file, File.join(TMP_DIR, File.basename(file)))
+  end
+  at_exit { empty_temp_dir }
+end
+
+def refresh_temp_dir
+  empty_temp_dir
+  fill_temp_dir
+end
+
+def benchmark_tests
+  refresh_temp_dir if temp_dir_empty?
+  system("bundle exec ruby -Ilib:test #{Shellwords.shellescape(TMP_DIR)}/*.rb")
+end
+
+def current_branch
+  @current_branch ||= `cat .git/HEAD | cut -d/ -f3,4,5`.chomp
+end
+
+def checkout_ref(ref)
+  puts `git checkout #{ref}`.chomp
+  abort "Checkout failed: #{ref}, #{$?.exitstatus}" unless $?.success?
+end
+
+def benchmark
+  refresh_temp_dir
+  ref  = current_branch
+
+  actual = run_benchmark_at_ref ref
+  master = run_benchmark_at_ref 'master'
+
+  checkout_ref(ref)
+
+  puts "\n\nResults ============================\n"
+  puts "------------------------------------~> (Branch) MASTER"
+  puts master
+  puts "------------------------------------\n\n"
+
+  puts "------------------------------------~> (Actual Branch) #{ref}"
+  puts actual
+  puts "------------------------------------"
+end
+
+def run_benchmark
+  response = Benchmark.realtime {
+    benchmark_tests
+  }
+  benchmark_tests
+  response
+end
+
+def run_benchmark_at_ref(ref)
+  checkout_ref(ref)
+  run_benchmark
+end
+
+if $0 == __FILE__
+  benchmark
+end

test/benchmark/serialization_benchmark.rb

@@ -1,24 +1,160 @@
-require 'test_helper'
+require 'bundler/setup'
+
+require 'rails'
+require 'action_controller'
+require 'action_controller/test_case'
+require 'action_controller/railtie'
+require 'active_support/json'
+require 'minitest/autorun'
+# Ensure backward compatibility with Minitest 4
+Minitest::Test = MiniTest::Unit::TestCase unless defined?(Minitest::Test)
+
+class Foo < Rails::Application
+  if Rails.version.to_s.start_with? '4'
+    config.action_controller.perform_caching = true
+    config.active_support.test_order         = :random
+    ActionController::Base.cache_store       = :memory_store
+    config.eager_load = false
+    config.secret_key_base = 'abc123'
+  end
+end
+
+require 'active_model_serializers'
+
+# require 'fixtures/poro'
+
+module TestHelper
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    get ':controller(/:action(/:id))'
+    get ':controller(/:action)'
+  end
+
+  ActionController::Base.send :include, Routes.url_helpers
+end
+
+ActionController::TestCase.class_eval do
+  def setup
+    @routes = TestHelper::Routes
+  end
+end
+
+class Model
+  def initialize(hash = {})
+    @attributes = hash
+  end
+
+  def cache_key
+    "#{self.class.name.downcase}/#{id}-#{updated_at}"
+  end
+
+  def updated_at
+    @attributes[:updated_at] ||= Time.current.to_i
+  end
+
+  def read_attribute_for_serialization(name)
+    if name == :id || name == 'id'
+      id
+    else
+      @attributes[name]
+    end
+  end
+
+  def id
+    @attributes[:id] || @attributes['id'] || object_id
+  end
+
+  def to_param
+    id
+  end
+
+  def method_missing(meth, *args)
+    if meth.to_s =~ /^(.*)=$/
+      @attributes[Regexp.last_match(1).to_sym] = args[0]
+    elsif @attributes.key?(meth)
+      @attributes[meth]
+    else
+      super
+    end
+  end
+end
+AuthorSerializer = Class.new(ActiveModel::Serializer) do
+  attributes :id, :name
+
+  has_many :posts, embed: :ids
+  has_one :bio
+end
+BlogSerializer = Class.new(ActiveModel::Serializer) do
+  attributes :id, :name
+end
+CommentSerializer = Class.new(ActiveModel::Serializer) do
+  attributes :id, :body
+
+  def custom_options
+    options
+  end
+end
+PostSerializer = Class.new(ActiveModel::Serializer) do
+  attributes :id, :title, :body
+
+  has_many :comments, serializer: CommentSerializer
+  belongs_to :blog, serializer: BlogSerializer
+  belongs_to :author, serializer: AuthorSerializer
+
+  def blog
+    Blog.new(id: 999, name: 'Custom blog')
+  end
+
+  def custom_options
+    options
+  end
+end
+
+CachingAuthorSerializer = Class.new(AuthorSerializer) do
+  cache key: 'writer'
+end
+CachingCommentSerializer = Class.new(CommentSerializer) do
+  cache expires_in: 1.day
+end
+CachingPostSerializer = Class.new(PostSerializer) do
+  cache key: 'post', expires_in: 0.1
+  belongs_to :blog, serializer: BlogSerializer
+  belongs_to :author, serializer: CachingAuthorSerializer
+  has_many :comments, serializer: CachingCommentSerializer
+end
+
+Comment  = Class.new(Model)
+Author   = Class.new(Model)
+Post     = Class.new(Model)
+Blog     = Class.new(Model)
 
 module ActionController
   module Serialization
     class SerializerTest < ActionController::TestCase
       class PostController < ActionController::Base
-
         def render_with_cache_enable
-          comment = Comment.new({ id: 1, body: 'ZOMG A COMMENT' })
+          comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
           author  = Author.new(id: 1, name: 'Joao Moura.')
-          post    = Post.new({ id: 1, title: 'New Post', blog:nil, body: 'Body', comments: [comment], author: author })
+          post    = Post.new(id: 1, title: 'New Post', blog: nil, body: 'Body', comments: [comment], author: author)
 
           render json: post
         end
+
+        def render_with_cache_disabled
+          comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
+          author  = Author.new(id: 1, name: 'Joao Moura.')
+          post    = Post.new(id: 1, title: 'New Post', blog: nil, body: 'Body', comments: [comment], author: author)
+
+          render json: post, serializer: CachingPostSerializer
+        end
       end
 
       tests PostController
 
-      def test_render_with_cache_enable
+      def test_render_benchmark
         ActionController::Base.cache_store.clear
         get :render_with_cache_enable
+        get :render_with_cache_disabled
 
         expected = {
           id: 1,
@@ -42,7 +178,25 @@ def test_render_with_cache_enable
         assert_equal 'application/json', @response.content_type
         assert_equal expected.to_json, @response.body
 
-        get :render_with_cache_enable
+        n = 1_000
+        Benchmark.bmbm do |x|
+          x.report('cache') do
+            ActionController::Base.cache_store.clear
+            i = 0
+            while i < n
+              get :render_with_cache_enable
+              i += 1
+            end
+          end
+          x.report('no cache') do
+            ActionController::Base.cache_store.clear
+            i = 0
+            while i < n
+              get :render_with_cache_disabled
+              i += 1
+            end
+          end
+        end
         assert_equal expected.to_json, @response.body
       end
     end