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Clean Test Code

Clean Test Code

Rubyで読みやすいテストコードを書くためのコツについてまとめました

6ac7c50770603b53964d44db373e8e48?s=128

Shinichi Maeshima

May 18, 2017
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  1. Clean Test Code @willnet

  2. ࣗݾ঺հ • લౡਅҰ aka @willnet or @netwillnet • ginza.rb ͔Βདྷ·ͨ͠

    • ϑϦʔϥϯεRailsٕज़ސ໰ • https://github.com/willnet • https://twitter.com/netwillnet • http://blog.willnet.in
  3. ٕज़ސ໰ۀͬͯͳʹ΍ͬͯΔͷ Railsͷ஌ݟΛձࣾʹఏڙ͢Δ࢓ࣄ • ձࣾ૑ੈظʹෛ࠴ΛͨΊͯ͠·͕ͬͨͦΖͦΖฦ͍ͨ͠ • ผͷݴޠͰ։ൃ͍͕ͯͨ͠Rubyʹ৐Γ׵͍͑ͨ • ελʔτ͔࣌Βෛ࠴ΛஷΊͣʹRailsΞϓϦέʔγϣϯΛ։ൃ ͍ͨ͠

  4. ۩ମతʹԿ΍ͬͯΔͷ • Rails΍γεςϜઃܭʹؔ͢Δ࣭໰ʹ౴͑Δ • ίʔυϨϏϡʔ • ࣾ಺ษڧձͷ։࠵ • ίʔυΛॻ͘ •

    ࠾༻ͷ૬ஊ৐Δ • etc
  5. Railsͷ஌ݟΛෳ਺ͷձ ࣾʹఏڙ࢝͠Ίͯ1೥൒ ͘Β͍

  6. ৭ΜͳॴͰಉ͜͡ͱݴͬ ͯΔؾ͕͢Δͧʁ

  7. Α͘આ໌͢Δ಺༰Λ·ͱ ΊΔͱ…

  8. ʮ͜ΕಡΜͰ͓͍ͯͩ͘ ͍͞ʯͰऴΘͬͯ΂Μ Γʂ

  9. Α͘આ໌͢Δ಺༰Λ·ͱΊͨྫ

  10. ࠓճ͸ςετίʔυͷॻ ͖ํʹ͍ͭͯ·ͱΊ·͠ ͨ

  11. ͳͥςετίʔυ͔ ΞϓϦέʔγϣϯίʔυʹ͸RubyͰՄಡੑΛอͭͨΊͷํ๏ɺ RailsͰՄಡੑΛอͭͨΊͷํ๏ͱ΋ʹॻ੶΍ωοτهࣄ͕͋Δ • 7 Patterns to Refactor Fat ActiveRecord

    Models • ΦϒδΣΫτࢦ޲ઃܭ࣮ફΨΠυ • RubyʹΑΔσβΠϯύλʔϯ
  12. ςετίʔυ ςετίʔυ΋ΞϓϦέʔγϣϯίʔυͱಉ͘͡୯ͳΔRubyͷί ʔυͳͷͰ͕͢ɺଟগؾΛ͚ͭͳ͍ͱμϝͳϙΠϯτ͕͋Δ ͔͠͠ॻ੶΍ωοτهࣄͰ͸͋·Γ৮ΕΒΕ͍ͯͳ͍

  13. ςετίʔυ͸௕͍

  14. ςετίʔυ(RSpec)͸ ֊૚ߏ଄ʹͳ͍ͬͯΔ

  15. ςετίʔυ͸ந৅Խ͠ ͮΒ͍

  16. ͡Ό͋Ͳ͏ॻ͘ͱ͍͍ͷ ͔

  17. લఏ • RSpec • FactoryGirl

  18. 1.͍ͨͩ͠֊૚ߏ଄Λ࡞ Δ

  19. describeͱcontextΛਖ਼͘͠࢖͍෼͚Δ describeͱcontext͸ಉ͡ϝιου͕ͩɺ࣍ͷΑ͏ʹ࢖͍෼͚Δ ͜ͱͰԿΛςετ͍ͯ͠Δͷ͔ΛΘ͔Γ΍͘͢Ͱ͖Δɻ • describeͷҾ਺ʹ͸ςετͷର৅Λॻ͘ • contextͷҾ਺ʹ͸ςετΛ࣮ߦ͢ΔͨΊͷ৚݅Λॻ͘ ※describe, context, it

    ͷ֤Ҿ਺ʹ͖ͪΜͱͨ͠આ໌Λॻ͘ ͷ΋௒େࣄ!!!
  20. # ྫ describe Stack do let!(:stack) { Stack.new } describe

    '#push' do context 'จࣈྻΛpushͨ͠ͱ͖' do before { stack.push('value') } it 'ฦΓ஋͕pushͨ͠஋Ͱ͋Δ͜ͱ' do expect(stack).to eq 'value' end end context 'nilΛpushͨ͠৔߹' do it 'ArgumentErrorʹͳΔ͜ͱ' do expect { stack.push(nil) }.to raise_error(ArgumentError) end end end describe '#pop' do # ུ end end
  21. describeͷ֎ʹςετσʔλΛஔ͔ͳ͍ σʔλͷείʔϓΛߟྀͯ͠ɺςετέʔεʹෆཁͳσʔλ͕ଘࡏ ͢Δ͜ͱΛආ͚Δ

  22. # ҰݟDRYʹͰ͖ͦ͏ʹݟ͑Δ describe 'sample specs' do context 'a' do #

    ... end context 'b' do let!(:need_in_b_and_c) { ... } # ... end context 'c' do let!(:need_in_b_and_c) { ... } # ... end end
  23. # Ͱ΋͜͏มߋͯ͠͠·͏ͷ͸NG # ͦΕͧΕͷcontextͰඞཁͳσʔλͱඞཁͳ͍σʔλΛ೴಺ͰબΓ෼͚Δඞཁ͕ग़ͯ͘Δ describe 'sample specs' do let!(:need_in_b_and_c) {

    ... } context 'a' do # ... end context 'b' do # ... end context 'c' do # ... end end
  24. ྫ͚ͩͩͱʮผʹରͯ͠มΘΒͳ͘ͳ͍ʁʯͬͯࢥ͏͔΋͠Εͳ͍ ͚Ͳɺ࣮ࡍͷςετίʔυ͸let΍context͕΋ͬͱେྔʹ͋ͬͯ Θ͚Θ͔Βͳ͍ͷͰɺෆཁͳσʔλ͕ͳ͍ঢ়ଶΛอ࣋͢ΔͷϚδେ ࣄͳΜͰ͢Α

  25. 2. ґଘΛݮΒ͢

  26. FactoryGirlͷσϑΥϧτ஋ʹґଘͤ͞ͳ͍ FactoryGirlͷσϑΥϧτ஋͸͢΂ͯϥϯμϜ஋ʹ͢Δɻ ඞཁͳ஋ͷΈΛςετதͰ໌ࣔతʹࢦఆ͢Δ͜ͱʹΑΓɺʮ͜ͷς ετͰॏཁͳ஋͸ͳʹ͔ʯ͕Θ͔Γ΍͘͢ͳΔɻ

  27. ྑ͘ͳ͍ྫ FactoryGirl.define do factory :user do name 'willnet' active true

    end end
  28. describe User, type: :model do describe '#send_message' do let!(:sender) {

    create :user, name: 'maeshima' } let!(:receiver) { create :user, name: 'kamiya' } it 'ϝοηʔδ͕ਖ਼͘͠ૹΒΕΔ͜ͱ' do expect { sender.send_message(receiver: receiver, body: 'hello!') } .to change { Message.count }.by(1) end end end
  29. ্༙͖͕Δٙ໰ • User#active #=> falseͷͱ͖͸Ͳ͏ͳΔʁ • User#nameͬͯઃఆ͢Δඞཁ͋Δͷʁ

  30. Α͍ྫ FactoryGirl.define do factory :user do sequence(:name) { |i| "test#{i}"}

    active { [true, false].sample } end end
  31. describe User, type: :model do describe '#send_message' do let!(:sender) {

    create :user } let!(:receiver) { create :user } it 'ϝοηʔδ͕ਖ਼͘͠ૹΒΕΔ͜ͱ' do expect { sender.send_message(receiver: receiver, body: 'hello!') } .to change { Message.count }.by(1) end end end
  32. ͜ΕͰ(ςετର৅ͷίʔυΛಡ·ͳͯ͘΋)࣍ͷ͜ͱ͕Θ͔Δ • User#name͕User#send_messageͷಈ࡞ʹӨڹ͠ͳ͍ • User#active͕User#send_messageͷಈ࡞ʹӨڹ͠ͳ͍ σϑΥϧτ஋͕มߋ͞ΕͨΒςετ͕ίέΔΈ͍ͨͳ͜ͱ΋ͳ͘ͳ Δ

  33. FactoryGirlͰbelongs_toҎ֎ͷؔ࿈Λσϑ ΥϧτͰ࡞੒͠ͳ͍ has_manyͳͲͷؔ࿈ઌΛσϑΥϧτͷఆٛͰੜ੒ͯ͠͠·͏ͱڧ ྽ͳґଘؔ܎ʹͳͬͯ͠·͏ͷͰආ͚Δ

  34. ѱ͍ྫ FactoryGirl.define do factory :user do sequence(:name) { |i| "username#{i}"

    } after(:create) do |user, evaluator| create_list(:post, 2, user: user) end end end
  35. RSpec.describe User, type: :model do describe '#posts_ordered_by_popularity' do let!(:user) {

    create(:user) } let!(:post_popular) do post = user.posts[0] post.update(popularity: 5) post end let!(:post_not_popular) do post = user.posts[1] post.update(popularity: 1) post end it 'return posts ordered by populality' do expect(user.posts_ordered_by_popularity).to eq [post_popular, post_not_popular] end end end
  36. • after(:create)Ͱؔ࿈ઌΛੜ੒͍ͯ͠ΔͨΊɺؔ࿈ઌͷݸ਺ ΍ଐੑ͕ઃఆͰ͖ͳ͍ • ࠷ऴతʹͲΜͳσʔλ͕ἧ͍ͬͯΔͷ͔େมΘ͔Γʹ͍͘

  37. ྑ͍ྫ FactoryGirl.define do factory :user do sequence(:name) { |i| "username#{i}"

    } trait(:with_posts) do after(:create) do |user, evaluator| create_list(:post, 2, user: user) end end end end
  38. RSpec.describe User, type: :model do describe '#posts_ordered_by_popularity' do let!(:user) {

    create(:user) } let!(:post_popular) { create :post, user: user, popularity: 5 } let!(:post_not_popular) { create :post, user: user, popularity: 1 } it 'return posts ordered by populality' do expect(user.posts_ordered_by_popularity).to eq [post_popular, post_not_popular] end end end
  39. ೔࣌ʹ(ͳΔ΂͘)ґଘͤ͞ͳ͍ ೔࣌ΛऔΓѻ͏ςετΛॻ͘৔߹ɺઈର࣌ؒΛ࢖͏ඞཁ͕ͳ͍έʔ εͰ͋Ε͹ͳΔ΂͘ݱࡏ೔͔࣌Βͷ૬ର࣌ؒΛར༻͢Δͷ͕ྑ͍ɻ ͦͷํ͕࣮૷ͷෆ۩߹ʹؾ͚ͮΔՄೳੑ͕૿͢ɻ

  40. # ѱ͍ྫ class Post < ApplicationRecord # όάؚ͕·Ε͍ͯΔ scope :last_month_published,

    -> { where(publish_at: (Time.zone.now - 31.days).all_month) } end RSpec.describe Post, type: :model do describe '.last_month_published' do let!(:april_1st) { create :post, publish_at: Time.zone.local(2017, 4, 1) } let!(:april_30th) { create :post, publish_at: Time.zone.local(2017, 4, 30) } before do create :post, publish_at: Time.zone.local(2017, 5, 1) create :post, publish_at: Time.zone.local(2017, 3, 31) end it 'return published posts in last month' do Timecop.travel(2017, 5, 6) do # ςετ͸௨Δ expect(Post.last_month_published).to contain_exactly(april_1st, april_30th) end end end end
  41. # ྑ͍ྫ # ઈରͰ͸ͳ͍͕ෆ۩߹ʹؾͮ͘Մೳੑ͕૿͢ RSpec.describe Post, type: :model do describe

    '.last_month_published' do let!(:now) { Time.zone.now } let!(:last_beginning_of_month) { create :post, publish_at: 1.month.ago(now).beginning_of_month } let!(:last_end_of_month) { create :post, publish_at: 1.month.ago(now).end_of_month } before do create :post, publish_at: now create :post, publish_at: 2.months.ago(now) end it 'return published posts in last month' do expect(Post.last_month_published).to contain_exactly(last_beginning_of_month, last_end_of_month) end end end
  42. 3. લఏ৚݅ΛΘ͔Γ΍ ͘͢͢Δ

  43. updateͰσʔλΛมߋ͠ͳ͍ FactoryGirlͰ࡞੒ͨ͠ϨίʔυதͷΧϥϜΛupdateϝιου Ͱมߋ͢Δͱɺ࠷ऴతͳϨίʔυͷঢ়ଶ͕Θ͔Γʹ͘͘ͳΔ͠ɺς ετʹґଘ͍ͯ͠Δଐੑ΋Θ͔Γʹ͘͘ͳΔͷͰආ͚Δɻ

  44. # ѱ͍ྫ describe Post do let!(:post) { create :post }

    describe '#published?' do subject { post.published? } context 'when the post has already published' do it { is_expected.to eq true } end context 'when the post has not published' do before { post.update(publish_at: nil) } it { is_expected.to eq false } end context 'when the post is closed' do before { post.update(status: :close) } it { is_expected.to eq false } end context 'when the title includes "[WIP]"' do before { post.update(title: '[WIP]hello world') } it { is_expected.to eq false } end end end
  45. letΛ্ॻ͖͠ͳ͍ ઌఔͷupdateͷ࿩ͱಉ͡ɻ֤ςετͷલఏ৚͕݅Θ͔ΓͮΒ͘ͳ ΔͷͰආ͚Δ

  46. # ѱ͍ྫ describe Post do let!(:post) { create :post, title:

    title, status: status, publish_at: publish_at } let(:title) { 'hello world' } let(:status) { :open } let(:publish_at) { Time.zone.now } describe '#published?' do subject { post.published? } context 'when the post has already published' do it { is_expected.to eq true } end context 'when the post has not published' do let(:publish_at) { nil } it { is_expected.to eq false } end context 'when the post is closed' do let(:status) { :close } it { is_expected.to eq false } end context 'when the title includes "[WIP]"' do let(:title) { '[WIP]hello world'} it { is_expected.to eq false } end end end
  47. 4. ந৅Խ͢Δͱ͖͸Α ͘ߟ͑ͯ

  48. shared_examples͸Α͘ߟ͑ͯ࢖͏ shared_examplesΛར༻͢ΔͱίʔυͷॏෳΛ࡟আͰ͖Δ͕ɺॻ ͖ํʹΑͬͯ͸͔͑ͬͯՄಡੑΛམͱ͢͜ͱ͕͋Δɻ

  49. # ѱ͍ྫ # Ҿ਺ͱͯ͠౉͞Ε༵ͨ೔ʹରԠͨ͠෼͚ͩϙΠϯτΛ૿΍͢ϝιου # `Point#increase_by_day_of_the_week`Λςετ͍ͯ͠Δ RSpec.describe Point, type: :model

    do describe '#increase_by_day_of_the_week' do let(:point) { create :point, point: 0 } it_behaves_like 'point increasing by day of the week', 100 do let(:wday) { 0 } end it_behaves_like 'point increasing by day of the week', 50 do let(:wday) { 1 } end it_behaves_like 'point increasing by day of the week', 30 do let(:wday) { 2 } end # ... end end
  50. ͜Εݟͯͳʹ͕Ͳ͏ͳͬͯΔͷ͔͙͢ཧղͰ͖·͔ͨ͠ʁ

  51. ఆٛ͸ͪ͜Β RSpec.shared_examples 'point increasing by day of the week' do

    |expected_point| it "increase by #{expected_point}" do expect(point.point).to eq 0 point.increase_by_day_of_the_week(wday) expect(point.point).to eq expected_point end end
  52. # ѱ͍ྫ(࠶ܝ) # - લఏ৚͕݅ଟ͍ # - ఆ͕ٛ෼ࢄ͍ͯ͠Δ RSpec.describe Point,

    type: :model do describe '#increase_by_day_of_the_week' do let(:point) { create :point, point: 0 } it_behaves_like 'point increasing by day of the week', 100 do let(:wday) { 0 } end it_behaves_like 'point increasing by day of the week', 50 do let(:wday) { 1 } end it_behaves_like 'point increasing by day of the week', 30 do let(:wday) { 2 } end # ... end end
  53. # shared_examples Λ࢖ͬͨ··ՄಡੑΛଟগ૿ͨ͠ྫ RSpec.describe Point, type: :model do describe '#increase_by_day_of_the_week'

    do let(:point) { create :point, point: 0 } context 'on sunday' do let(:wday) { 0 } it_behaves_like 'point increasing by day of the week', expected_point: 100 end context 'on monday' do let(:wday) { 1 } it_behaves_like 'point increasing by day of the week', expected_point: 50 end context 'on tuesday' do let(:wday) { 2 } it_behaves_like 'point increasing by day of the week', expected_point: 30 end # ... end end
  54. # ϒϩοΫҾ਺ΛύϥϝʔλҾ਺ʹͨ͠ RSpec.shared_examples 'point increasing by day of the week'

    do |expected_point:| it "increase by #{expected_point}" do expect(point.point).to eq 0 point.increase_by_day_of_the_week(wday) expect(point.point).to eq expected_point end end
  55. # shared_examples ΛࣙΊͨྫ RSpec.describe Point, type: :model do describe '#increase_by_day_of_the_week'

    do let(:point) { create :point, point: 0 } context 'on sunday' do let(:wday) { 0 } it "increase by 100" do expect(point.point).to eq 0 point.increase_by_day_of_the_week(wday) expect(point.point).to eq 100 end end context 'on monday' do let(:wday) { 1 } it "increase by 50" do expect(point.point).to eq 0 point.increase_by_day_of_the_week(wday) expect(point.point).to eq 50 end end # ུ end end
  56. it_behaves_like '◦◦'` ʮ◦◦ͷΑ͏ʹৼΔ෣͏ʯͰදݱͰ͖ͳ͍Α͏ͳέʔεͰ͸߇͑ͨ ΄͏͕Α͍ͷͰ͸

  57. ʮԶͳΒ͜͏ॻ͘ʯΈ͍ͨͳ࿩ืू͠ ͍ͯ·͢

  58. ࠓ೔ͷ࿩͸࣍ͷGitHubϨϙδτϦʹ͍͍ͩͨ· ͱΊͯ·͢ ࠓ೔࿩ͨ͠Ҏ֎ͷ߲໨΋͋Γ·͢ https://github.com/willnet/rspec-style-guide

  59. ποίϛืू Issue, Pull Request͓·͍ͪͯ͠·͢

  60. Happy Testing!