使用 Jest 進行 Front-End Unit Test

* Frameworks
* Jest 基本設定
* Enzyme
* 語法與規則
* 各部分 Test 重點與方法
* 其他小技巧
* Coverage

文章：https://blog.patw.me/archives/1310/write-frontend-unit-tests-with-jest/

Transcript

1. ֵአ Jest 蝱ᤈ Front-End Unit Test
   Patrick Wang (patw)
   2016/09/26
   

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2. य़姛
   

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3. • Frameworks
   • Jest च๜戔ਧ
   • Enzyme
   • 承ဩ膏憒㳷
   • ݱ蟂獤 Test ᯿讨膏ොဩ
   • ٌ犢ੜದૣ
   • Coverage
   

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4. Frameworks
   

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5. Frameworks
   • Unit Test
   • Jasmine
   • Mocha, Chai, Sinon
   • Jest
   • AVA
   

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6. Assertion Libraries
   http://reactmad-testing.surge.sh/#/4
   

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7. Frameworks
   • E2E Test
   • Casper.js
   • Protractor
   • Nightwatch.js
   • CodeceptJS
   http://reactmad-testing.surge.sh/#/5
   

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8. Jest च๜戔ਧ
   

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9. ਞ蕕 & 戔ਧ
   jest & enable babel
   .babelrc
   

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10. npm scripts
    package.json
    瞱媲緳፡
    叨ኞ coverage 奾ຎ
    ᪒介手
    

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11. jest configuration
    package.json
    import ᪠䕩
    ࣁ᪒介手ԏ獮ጱ絑ह伛猋戔ਧ
    懯獈 coverage ጱፓ袅
    stub scss 䲆礯
    介手脻๜ጱ䲆ݷ pattern
    

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12. jest configuration
    jest/setupTests.js
    蝡螲ฎ傶ԧ mock ധ localStorage
    

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13. jest configuration
    jest/styleStub.js
    If you want to test classname (CSS Modules)…
    e.g., styles.foobar === 'foobar'
    Notice that Proxy is enabled in Node.js v6.* by default; if you are not on Node v6.* yet, make sure
    you invoke Jest using node --harmony_proxies node_modules/.bin/jest.
    

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14. Enzyme
    

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15. Enzyme
    • by Airbnb
    • ੗蕕ԧ React ጱਥො介手ૡٍ牧䢐磪觊犲 jQuery ጱ
    螡䢔瑊 API牧介手砰䌃Ӥๅො׎
    

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16. Enzyme - find
    • ֵአ React TestUtils 螡玲粬ਧፓ秂ጱ API物

    TestUtils.findRenderedDOMComponentWithXXXX
    • ֵአ Enzyme ݝᥝ component.find(selector) ܨݢ物
    
    

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17. Enzyme
    • shallow
    • render
    • mount
    

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18. Enzyme - shallow
    • ੗蕕ਥොጱ shallow rendering
    • ݝ჉礕ᒫӞ䍅牧犋჉礕ৼزկ
    • 蝧ଶ盠
    • 犋ᓕ child component ጱᤈ傶牧介手᯿讨ݝฎ
    component ๜蛪
    

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19. Enzyme - render
    • 觊犲 shallow牧ֵ֕አ Cheerio ୚砻
    • 犋ݝ჉礕Ӟ䍅
    • API 蚤 shallow च๜ӤӞ膌
    

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20. Enzyme - mount
    • Full rendering
    • ፥䋿ጱ DOM ℄讨
    • మᥝ介手膏 DOM ጱ԰㵕膏盅媲叨ኞጱ虋玕ҁই
    Click 盅㳫ᴻԧӞ㮆 list ጱ殻ፓ҂
    • మᥝ介手ਠ碉ጱኞ޸蝰๗
    

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21. 承ဩ膏憒㳷
    

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22. describe & it
    介手脻๜愊ᶎ䛑扗۱ೡӞ㮆౲ग़㮆describe璸牧ྯ㮆describe璸䛑
    扗۱ೡӞ㮆౲ग़㮆it璸牐
    describe璸圸傶"介手ॺկ"ҁtest suite҂牧蔭纈Ӟ奲ፘ橕ጱ介手牐
    ਙฎӞ㮆獢碍牧ᒫӞ㮆㷢碍ฎ介手ॺկጱݷ圸ҁ"ےဩ獢碍ጱ介手
    "҂牧ᒫԫ㮆㷢碍ฎӞ㮆䋿褬䁆ᤈጱ獢碍牐
    it璸圸傶"介手አֺ"ҁtest case҂牧蔭纈Ӟ㮆㻌加ጱ介手牧ฎ介手ጱ
    磧ੜ㻌֖牐ਙ犖ฎӞ㮆獢碍牧ᒫӞ㮆㷢碍ฎ介手አֺጱݷ圸ҁ"1 ے
    1 䛑扗缛ෝ 2"҂牧ᒫԫ㮆㷢碍ฎӞ㮆䋿褬䁆ᤈጱ獢碍牐
    http://www.ruanyifeng.com/blog/2015/12/a-mocha-tutorial-of-examples.html
    

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23. describe & it
    http://www.ruanyifeng.com/blog/2015/12/a-mocha-tutorial-of-examples.html
    import add from './add';
    import { expect } from 'chai';
    describe('ےဩ獢碍ጱ介手', function () {
    it('1 ے 1 䛑扗缛ෝ 2', function () {
    expect(add(1, 1)).to.be.equal(2);
    });
    });
    

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24. expect
    ಅ蘎"䥁᥺"牧疰ฎڣ䥁რ嘨ጱ䋿褬䁆ᤈ奾ຎ膏毆๗奾ຎ
    ฎ玽Ӟ膌牧ইຎ犋Ӟ膌疰瞦ڊӞ㮆梊藮牐
    http://www.ruanyifeng.com/blog/2015/12/a-mocha-tutorial-of-examples.html
    expect(add(1, 1)).to.be.equal(2);
    

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25. Jest ൉׀ጱ API
    • describe, it
    • xdescribe, xit - 䧙碻᪡螂介手碻ֵአ
    • fit - 㰍᪒種ྦྷ介手
    • beforeEach - ࣁྯ㮆介手ԏ獮᮷䁆ᤈ
    • afterEach - ࣁྯ㮆介手ԏ盅᮷䁆ᤈ
    http://www.ruanyifeng.com/blog/2015/12/a-mocha-tutorial-of-examples.html
    

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26. Jest ൉׀ጱ API
    • expect
    • .toBe(value)
    • .not
    • .toBeTruthy(), .toBeFalsy()
    • .toEqual(value)
    • .toBeCalled()
    • .toBeCalledWith(arg1, arg2, …)
    http://www.ruanyifeng.com/blog/2015/12/a-mocha-tutorial-of-examples.html
    

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27. 䌕礯ֵአጱ介手䲆礯޸ݷ憒㳷 (1/2)
    • ཿ介手ጱ source ݶ䍅樄Ӟ㮆 __tests__ ፓ袅
    • 䲆ݷ物{source 䲆ݷ}.test.js
    • ݚक़牧ࢩፓ獮ֵአ Ducks: Redux Reducer Bundles ጱ憒塅砰
    䌃 redux牧硲 reducers 膏 actions ጱ޸ݷ憒塅ইӥ物
    • Actions: {source 䲆ݷ}.actions.test.js
    • Reducers: {source 䲆ݷ}.reducers.test.js
    

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28. 䌕礯ֵአጱ介手䲆礯޸ݷ憒㳷 (2/2)
    • 舙襑ਧ嬝盄裾ጱ fake data牧ୌ捍ݚक़ୌӞඪ䲆礯硯ᗝ牧㪔
    硯ᗝࣁݶӞ䍅牐ٚෝ介手䲆礯Ӿ import 蝱㬵ֵአ牐
    • 犥 reselect ጱ newsByCat 傶ֺ牧׎ୌ缏ԧ物
    • newsByCat-newsByIdItemData.js物

    newsById 奾䯤ጱ؃虻碘
    • newsByCat-makeState.js物

    蜍獈 newsByCat-newsByIdItemData.js ጱ؃虻碘盅牧叨
    ڊӞ犩؃ state ׀扗 reselect 介手ֵአ
    

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29. ݱ蟂獤 Test ᯿讨膏ොဩ
    

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30. Component
    介手᯿讨
    1. Snapshot 介手 (Jest v14.0 ڊ匍)
    • 穉䌘叨ኞ HTML ጱ奾ຎฎ玽膏Ӥ稞盠ᆙፘᒧ
    • 犖磪Ոአࣁ reducer
    • https://facebook.github.io/jest/blog/2016/07/27/jest-14.html/
    2. Simulate ᤈ傶介手
    ࢩ種盠ᆙ犖ᥝ蝱 git
    

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31. Component - snapshot
    snapshot
    

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32. Component - simulate (with mount)
    

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33. Container
    介手᯿讨
    1. Container 膏ٌ Component ᮷磪ᤩ render ڊ㬵
    • 襑አ ۱蚏㬵
    2. ᤩ Mock ጱ Component 磪ᤩ call Ӟ稞
    

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34. Container
    伛猋؃虻碘牏አ Provider ۱蚏㬵牏㯽獈 context
    

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35. Container
    ᛔ૩ mock createStore
    

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36. Container
    Component 磪ᤩ call Ӟ稞
    磪 render 奾ຎ
    

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37. Reducer
    介手᯿讨
    1. 蜍獈 initial state 膏 action 盅牧蜴ࢧ毆๗ጱ state
    2. 蝫媲蜍獈 state 膏 action 盅牧膏 snapshots ፘᒧ
    

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38. Reducer
    

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39. Reducer - Snapshot test
    https://twitter.com/villeimmonen/status/772754403187126272
    

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40. snapshot አෝ reducer
    snapshot
    

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41. Action
    介手᯿讨
    1. 䁆ᤈ action 盅牧蜴ࢧ毆๗ጱ object (type 膏
    payloads)
    2. 瞚Ӥ牧֕Ӿ樌妿螂 mock 螂ጱ ajax
    

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42. Action
    

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43. Action - mock ajax (1/4)
    • nock
    • mock the HTTP requests

    • redux-mock-store
    • apply the middleware to a mock store
    http://redux.js.org/docs/recipes/WritingTests.html#async-action-creators
    

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44. Action - mock ajax (2/4)
    

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45. Action - mock ajax (3/4)
    

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46. Action - mock ajax (4/4)
    ಩ܻ๜ ajax ጱ蟂犩 mock ധ
    犖ݢ犥አ ES7 await/async
    

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47. Reselect
    介手᯿讨
    1. 懯ᓒ奾ຎ膏毆๗ፘᒧ
    2. 蜍獈ፘݶጱ独牧犋䨝᯿碝懯ᓒ (recomputations)
    

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48. Reselect
    ࣁ beforeEach Ӿ懿஑ jest.resetModules()
    

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49. Router (1/4)
    介手᯿讨
    1. params / path ፘᒧ
    2. property ፘᒧҁই物䢐磪 hideTopAd҂
    3. Component ፘᒧ
    

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50. Router (2/4)
    

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51. Router (3/4)
    

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52. Router (4/4)
    

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53. ٌ犢ੜದૣ
    

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54. jest.mock(module_path, fn) (1/2)
    • Jest 粬ᜋԏӞ牧虏介手䌕ဳࣁ匍ࣁ介手ጱ秇奲๜蛪牧
    import ጱ module mock ധ牧螨ع୽段介手Ӿጱ秇
    奲牐
    • ֕ Jest v15 蚏牧automocking 毆戔ฎ橕ധጱ牐ҁਥ
    ො藯ก҂
    

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55. jest.mock(module_path, fn) (2/2)
    

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56. jest.resetModules()
    嘦狒 import/require ጱ module ䷱磪ᤩ࿱礕牐
    蝢ଉ硯ࣁ beforeEach() Ӿ物
    

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57. jest.fn() (1/2)
    ಩ᒫӣො౲㯽獈ጱ function mock 蚏㬵牧ই種㰍ᥝ介手
    ᤩ call ጱ稞碍౲ฎᴫ癲㯽獈ጱ㷢碍ฎ玽ྋ嘦ܨݢ牐
    ֺ物ࣁ纷ୗ嘨Ӿ޷ݞԧ ga/piwik ጱ纷ୗ嘨牧֕介手碻䷱磪஠ᥝ

    斉獈 ga牧ݝᥝ jest.fn() mock 蚏㬵疰অ牐
    

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58. jest.fn() (2/2)
    介手ݢ犥介扗 mock 螂ጱ function ฎ玽ᤩ call牫

    ᤩ call ጱ碻狡ᴫ癲Ջ讕㷢碍牫
    ࣁ beforeEach Ӿአ mockFn.mockClear() 嘦狒ྯ稞᮷
    ᯿ᗝ制眲ҁ㯽獈㷢碍牏稞碍҂牐
    

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59. timer ፘ橕 mock (1/3)
    朼䌘 timer 犖ݢ犥 mock牧jest.useFakeTimers()
    Instructs Jest to use fake versions of the standard
    timer functions (setTimeout, setInterval, clearTimeout,
    clearInterval, nextTick, setImmediate and
    clearImmediate).
    https://facebook.github.io/jest/docs/timer-mocks.html#content
    

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60. timer ፘ橕 mock (2/3)
    https://facebook.github.io/jest/docs/timer-mocks.html#content
    

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61. timer ፘ橕 mock (3/3)
    https://facebook.github.io/jest/docs/timer-mocks.html#content
    

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62. Async Test
    Async/Await
    Error Handling
    https://facebook.github.io/jest/docs/tutorial-async.html#content
    

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63. Coverage
    

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64. Coverage
    jest 獉ୌ coverage牐౯㮉犖ࣁ package.json 戔ਧঅ script ԧ牐
    䨝礬硁 package.json Ӿ jest.collectCoverageFrom 戔ਧጱፓ袅塅瑻懯ᓒ coverage牐

    叨ኞ蝡䰬ጱ奾ຎ物
    

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65. Coverage
    犖䨝ࣁ coverage/ ፓ袅ҁ毆戔҂Ӿ叨ኞ HTML 粚ጱ䁭ޞ物
    

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66. Codecov
    

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67. Codecov
    

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68. 㷢ᘍ虻碘
    

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69. 㷢ᘍ虻碘
    • Give Jest Another Go

    https://medium.com/@jrwebdev/give-jest-another-go-86ca3d00f75
    • Unit Test Redux Container Components - Part 1

    http://www.wsbrunson.com/react/redux/test/2016/05/08/testing-redux-containers.html
    • React.js 101 - React 介手獈槹硽䋊

    https://github.com/kdchang/reactjs101/tree/master/Appendix03
    • Testing React Components With Enzyme

    http://codeheaven.io/testing-react-components-with-enzyme/
    • 介手໛礍 Mocha 䋿ֺ硽纷

    http://www.ruanyifeng.com/blog/2015/12/a-mocha-tutorial-of-examples.html
    • Testing Your React (and redux) Applications (Youtube video)

    https://www.youtube.com/watch?v=n49QKIzS_Ik
    • 獮ᒒ介手ૡٍ墋㻌碉ቘ޾穉斃

    https://github.com/ellisMing/introduction-angular-test#獮ᒒ介手ૡٍ墋㻌碉ቘ޾穉斃
    

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70. Thanks! <(_ _)>
    

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