Practical Faster Testing (With Rails)

From the Scottish Ruby Conference Fringe event 2012.

A short talk with some tips and advice on how to get faster tests with Rails.

Transcript

1. PRACTICAL
   FASTER TESTING
   JON ROWE
   WITH RAILS*
   Sunday, 1 July 12
   

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2. PRACTICAL
   FASTER TESTING
   JON ROWE
   *SORT OF...
   WITH RAILS*
   Sunday, 1 July 12
   

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3. DISCLAIMER
   I’m not going to offer tips on how to
   speed up your existing legacy tests.
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4. WHY FAST?
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5. WHY FAST?
   We know this right?
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6. WHY FAST?
   We know this right?
   Shorten the feedback cycle
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7. WHY FAST?
   We know this right?
   Shorten the feedback cycle
   Focus
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8. WHY FAST?
   We know this right?
   Shorten the feedback cycle
   Focus
   Actually write tests
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9. WHY FAST?
   We know this right?
   Shorten the feedback cycle
   Focus
   Actually write tests
   “Feel Awesome”@kytrinyx
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10. SAD TRUTH
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11. SAD TRUTH
    No test is faster than no tests
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12. SAD TRUTH
    No test is faster than no tests
    F5DD
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13. SAD TRUTH
    No test is faster than no tests
    F5DD
    Laziness is easy
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14. SO WHY SLOW?
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15. SO WHY SLOW?
    “Your code makes it slow”
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16. SO WHY SLOW?
    “Your code makes it slow”
    Your tests make it slow
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17. SO WHY SLOW?
    “Your code makes it slow”
    Your tests make it slow
    And…
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18. FACT
    Rails is what makes your tests slow
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19. FACT
    Rails is what makes your tests slow
    But that’s not Rails’ fault
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20. FACT
    Rails is what makes your tests slow
    But that’s not *all* Rails’ fault
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21. THE RAILS WAY
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22. THE RAILS WAY
    Auto load *everything*
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23. THE RAILS WAY
    Auto load *everything*
    Integration test
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24. THE RAILS WAY
    Auto load *everything*
    Integration test
    Magic!
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25. THE ENEMY
    require 'spec_helper'
    require 'rspec/rails'
    require 'rails'
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26. THE ENEMY
    Booting rails is slow
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27. THE ENEMY
    Booting rails is slow
    Unnecessary for unit testing
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28. CONTROLLERS
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29. CONTROLLERS
    When to test
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30. CONTROLLERS
    When to test
    Don’t?
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31. CONTROLLERS
    When to test
    Don’t?
    Do?
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32. class SensibleController < ApplicationController
    def index
    @objects = Record.all
    end
    def new
    @object = Record.new
    end
    def create
    Record.create params[:record]
    redirect_to index_path
    end
    def edit
    @record = Record.find(params[:id])
    end
    def update
    Record.find(params[:id]).update_attributes params[:record]
    redirect_to index_path
    end
    end
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33. class SensibleController < ApplicationController
    def create
    Record.create! params[:record]
    redirect_to index_path
    rescue
    @record = Record.new params[:record]
    render :new
    end
    def edit
    @record = Record.find(params[:id])
    rescue NotFound
    redirect_to index_path
    end
    def update
    Record.find(params[:id]).update_attributes params[:record]
    redirect_to index_path
    rescue Validations
    @record = Record.new params[:record]
    render :edit
    rescue NotFound
    redirect_to index_path
    end
    end
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34. class UberDeathController
    def index
    @bugs =
    if params[:q].blank? && params[:c].blank? && params[:m].blank? && params[:order].bla
    Bug.by_gnar_factor.paginate :per_page => @per_page, :page => params[:page]
    elsif params[:q].blank? && !params[:c].blank? && params[:m].blank? && params[:order]
    Bug.for_section(params[:c]).by_gnar_factor.paginate :per_page => @per_page, :page
    elsif params[:c].blank? && !params[:q].blank? && params[:m].blank? && params[:order]
    Bug.search_for(params[:q]).by_gnar_factor.paginate :per_page => @per_page, :page =
    elsif !params[:c].blank? && !params[:q].blank? && params[:m].blank? && params[:order
    Bug.search_for(params[:q]).by_gnar_factor.for_section(params[:c]).paginate :per_pa
    elsif params[:c].blank? && params[:q].blank? && !params[:m].blank? && params[:order]
    Bug.master_bugs.by_gnar_factor.paginate :per_page => @per_page, :page => params[:p
    elsif !params[:c].blank? && params[:q].blank? && !params[:m].blank? && params[:order
    Bug.master_bugs.by_gnar_factor.for_section(params[:c]).paginate :per_page => @per_
    elsif params[:c].blank? && !params[:q].blank? && !params[:m].blank? && params[:order
    Bug.master_bugs.by_gnar_factor.search_for(params[:q]).paginate :per_page => @per_p
    elsif !params[:c].blank? && !params[:q].blank? && !params[:m].blank? && params[:orde
    Bug.master_bugs.by_gnar_factor.search_for(params[:q]).for_section(params[:c]).pagi
    end
    end
    end
    STILL DONT TEST?
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35. THE TESTS
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36. THE TESTS
    Integration test
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37. THE TESTS
    Integration test
    Request Verbs
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38. THE TESTS
    Integration test
    Request Verbs
    Filters
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39. THE TESTS
    Integration test
    Request Verbs
    Filters
    Slow
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40. THE TESTS
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41. THE TESTS
    Unit test
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42. THE TESTS
    Unit test
    Skip filters
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43. THE TESTS
    Unit test
    Skip filters
    Focus on your code
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44. THE TESTS
    Unit test
    Skip filters
    Focus on your code
    Let Rails work
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45. INTEGRATION
    require 'spec_helper'
    describe ExampleWithModelController do
    describe 'post :create' do
    subject { post :create }
    it "creates a model" do
    expect { subject }.to change(RandomModel,:count).by(1)
    end
    it "redirects away" do
    subject.should redirect_to '/'
    end
    end
    end
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46. INTEGRATION
    require 'spec_helper'
    describe ExampleWithModelController do
    describe 'post :create' do
    before { RandomModel.stub(:create) }
    subject { post :create }
    it "creates a RandomModel" do
    RandomModel.should_receive(:create)
    subject
    end
    it "redirects away" do
    subject.should redirect_to '/'
    end
    end
    end
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47. UNIT
    require 'action_controller'
    require 'app/controllers/application_controller'
    require 'app/controllers/example_with_model_controller'
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48. class RandomModel; end
    describe ExampleWithModelController do
    describe '#create' do
    let(:controller) { described_class.new }
    before do
    controller.request = Struct.new(:parameters).new
    controller.stub(:redirect_to)
    end
    subject { controller.create }
    it "creates a RandomModel" do
    RandomModel.should_receive(:create)
    subject
    end
    it "redirects to away" do
    controller.should_receive(:redirect_to).with('/')
    subject
    end
    end
    end
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49. RESULTS (x100)
    ============================
    unit
    ============================
    0.000000 0.000000 1.140000 ( 1.149252)
    ============================
    integration
    ============================
    0.000000 0.010000 2.510000 ( 2.498981) (stubbed)
    0.000000 0.000000 3.070000 ( 3.175934) (full stack)
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50. RESULTS (x1000)
    ============================
    unit x1000
    ============================
    0.000000 0.020000 3.060000 ( 3.051226)
    ============================
    integration x1000
    ============================
    0.010000 0.020000 8.380000 ( 8.382151) (stubbed)
    0.010000 0.020000 13.160000 ( 15.175460) (full stack)
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51. YEAH...*
    *Caveats
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52. YEAH...*
    Controller stubbing (view isolation)
    *Caveats
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53. YEAH...*
    Controller stubbing (view isolation)
    What about my filters?
    *Caveats
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54. MODELS
    require 'active_record'
    config = YAML.load(File.open("config/database.yml"))["test"]
    ActiveRecord::Base.establish_connection(config)
    require 'app/models/random_model'
    0.310000 0.070000 0.380000 ( 0.540731)
    require 'spec_helper'
    1.300000 0.220000 1.520000 ( 1.756871)
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55. MODELS
    So not much improvement
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56. MODELS
    So not much improvement
    DB calls?
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57. MODELS
    So not much improvement
    DB calls?
    How can we make these faster?
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58. MODULAR
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59. MODULAR
    Injecting your objects
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60. MODULAR
    Injecting your objects
    Code faster?
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61. MODULAR
    Injecting your objects
    Code faster?
    Slower? No!
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62. MODULAR
    Injecting your objects
    Code faster?
    Slower? No!
    Tests faster? YES!
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63. MODULAR
    Injecting your objects
    Code faster?
    Slower? No!
    Tests faster? YES!
    Less to load
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64. class ChangeStock
    def initialize(item)
    @item = item
    end
    def delta
    quantity - @item.quantity
    end
    def to(quantity)
    if quantity > @item.quantity
    @item.fee_generator.charge_increase delta
    end
    @item.set_quantity quantity
    @item.save!
    end
    end
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65. REFACTOR
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66. REFACTOR
    Separate from the framework
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67. REFACTOR
    Separate from the framework
    Write your own helpers
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68. REFACTOR
    Separate from the framework
    Write your own helpers
    Mocking/Stubbing
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69. BE SENSIBLE
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70. BE SENSIBLE
    Test when it makes sense
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71. BE SENSIBLE
    Test when it makes sense
    No hard and fast rules
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72. BE SENSIBLE
    Test when it makes sense
    No hard and fast rules
    Consider the value
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73. BOY SCOUT RULE
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74. BOY SCOUT RULE
    Always leave code cleaner
    than you found it
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75. BOY SCOUT RULE
    Always leave tests cleaner
    than you found them
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76. SUMMARY
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77. SUMMARY
    Require what you need
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78. SUMMARY
    Require what you need
    Unit test your units
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79. SUMMARY
    Require what you need
    Unit test your units
    Abstract away
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80. SUMMARY
    Require what you need
    Unit test your units
    Abstract away
    Integration/acceptance test framework
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81. SUMMARY
    Require what you need
    Unit test your units
    Abstract away
    Integration/acceptance test framework
    Don’t boot rails unless needed
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82. SUMMARY
    Require what you need
    Unit test your units
    Abstract away
    Integration/acceptance test framework
    Don’t boot rails unless needed
    Be sensible!
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83. THANKS
    Jon Rowe
    @jonrowe (twitter, github, etc)
    http://jonrowe.co.uk
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