通过构建自己的JavaScript测试框架来了解JS测试

function helloWorld() { 
  return 'Hello world!'; 
} 

describe('Hello world', () => { ① 
  it('says hello', () => { ② 
      expect(helloWorld())③.toEqual('Hello world!'); ④ 
  }); 
}); 

describe(string, function) 
it(string, function) 

node_prj 
    src/ 
        one.js 
        two.js 
    test/ 
        one.spec.js 
        two.spec.js 
    package.json 

{ 
  ..., 
  "script": { 
      "test": "jest" // or "jasmine" 
    } 
} 

mkdir kwuo 
cd kwuo 
npm init -y 

mkdir lib 

mkdir bin 

#!/usr/bin/env node 
 
process.title = 'kwuo' 
require('../lib/cli/cli') 

mkdir lib/cli 
touch lib/cli/cli.js 

describe('Hello world', () => {  
  it('says hello', () => {  
    expect(helloWorld()).toEqual('Hello world!'); 
  }); 
}); 

touch lib/index.js 

// lib/index.js 
 
const chalk = require('chalk') 
const log = console.log 
var beforeEachs = [] 
var afterEachs = [] 
var afterAlls = [] 
var beforeAlls = [] 
var Totaltests = 0 
var passedTests = 0 
var failedTests = 0 
var stats = [] 
var currDesc = { 
  it: [] 
} 
 
var currIt = {} 
 
function beforeEach(fn) { 
  beforeEachs.push(fn) 
} 
 
function afterEach(fn) { 
  afterEachs.push(fn) 
} 
 
function beforeAll(fn) { 
  beforeAlls.push(fn) 
} 
 
function afterAll(fn) { 
  afterAlls.push(fn) 
} 
 
function expect(value) { 
  return { 
 
    // Match or Asserts that expected and actual objects are same. 
    toBe: function(expected) { 
      if (value === expected) { 
        currIt.expects.push({ name: `expect ${value} toBe ${expected}`, status: true }) 
        passedTests++ 
      } else { 
        currIt.expects.push({ name: `expect ${value} toBe ${expected}`, status: false }) 
        failedTests++ 
      } 
    }, 
 
    // Match the expected and actual result of the test. 
    toEqual: function(expected) { 
      if (value == expected) { 
        currIt.expects.push({ name: `expect ${value} toEqual ${expected}`, status: true }) 
        passedTests++ 
      } else { 
        currIt.expects.push({ name: `expect ${value} toEqual ${expected}`, status: false }) 
        failedTests++ 
      } 
    } 
  } 
} 
 
function it(desc, fn) { 
  Totaltests++ 
  if (beforeEachs) { 
    for (var index = 0; index < beforeEachs.length; index++) { 
      beforeEachs[index].apply(this) 
    } 
  } 
  //var f = stats[stats.length - 1] 
  currIt = { 
    name: desc, 
    expects: [] 
  } 
  //f.push(desc) 
  fn.apply(this) 
  for (var index = 0; index < afterEachs.length; index++) { 
    afterEachs[index].apply(this) 
  } 
  currDesc.it.push(currIt) 
} 
 
function describe(desc, fn) { 
  currDesc = { 
    it: [] 
  } 
  for (var index = 0; index < beforeAlls.length; index++) { 
    beforeAlls[index].apply(this) 
  } 
  currDesc.name = desc 
  fn.apply(this) 
  for (var index = 0; index < afterAlls.length; index++) { 
    afterAlls[index].apply(this) 
  } 
  stats.push(currDesc) 
} 
 
exports.showTestsResults = function showTestsResults() { 
    console.log(`Total Test: ${Totaltests}     
Test Suites: passed, total 
Tests: ${passedTests} passed, ${Totaltests} total 
`) 
  const logTitle = failedTests > 0 ? chalk.bgRed : chalk.bgGreen 
  log(logTitle('Test Suites')) 
  for (var index = 0; index < stats.length; index++) { 
    var e = stats[index]; 
    const descName = e.name 
    const its = e.it 
    log(descName) 
    for (var i = 0; i < its.length; i++) { 
      var _e = its[i]; 
      log(`   ${_e.name}`) 
      for (var ii = 0; ii < _e.expects.length; ii++) { 
        const expect = _e.expects[ii] 
        log(`      ${expect.status === true ? chalk.green('√') : chalk.red('X') } ${expect.name}`) 
      } 
    } 
    log() 
  } 
} 
 
global.describe = describe 
global.it = it 
global.expect = expect 
global.afterEach = afterEach 
global.beforeEach = beforeEach 
global.beforeAll = beforeAll 
global.afterAll = afterAll 

expect(56).toBe(56) // 经过测试56预期会是56 
expect(func()).toEqual("nnamdi") // 该函数将返回一个等于“nnamdi”的字符串 

// lib/cli/cli.js 
const path = require('path') 
const fs = require('fs') 
const { showTestsResults } = require('./../') 

mkdir examples 
mkdir examples/math 
cd examples/math 
npm init -y 

mkdir src 
touch src/add.js src/sub.js 

// src/add.js 
function add(a, b) { 
    return a+b 
} 
 
module.exports = add 
 
// src/sub.js 
function sub(a, b) { 
    return a-b 
} 
 
module.exports = sub 

mkdir test 
touch test/add.spec.js test/sub.spec.js 

// test/sub.spec.js 
const sub = require('../src/sub') 
describe("Subtract numbers", () => { 
  it("should subtract 1 from 2", () => { 
    expect(sub(2, 1)).toEqual(1) 
  }) 
   
  it("should subtract 2 from 3", () => { 
    expect(sub(3, 2)).toEqual(1) 
  }) 
}) 
 
// test/add.spec.js 
const add = require('../src/add') 
describe("Add numbers", () => { 
  it("should add 1 to 2", () => { 
    expect(add(1, 2)).toEqual(3) 
  }) 
   
  it("should add 2 to 3", () => { 
    expect(add(2, 3)).toEqual(5) 
  }) 
}) 
describe('Concat Strings', () => { 
  let expected; 
  beforeEach(() => { 
    expected = "Hello"; 
  }); 
   
  afterEach(() => { 
    expected = ""; 
  }); 
   
  it('add Hello + World', () => { 
    expect(add("Hello", "World")) 
      .toEqual(expected); 
  }); 
}); 

{ 
  "name": "math", 
  "version": "1.0.0", 
  "description": "", 
  "main": "index.js", 
  "scripts": { 
    "test": "kwuo" 
  }, 
  "keywords": [], 
  "author": "Chidume Nnamdi <kurtwanger40@gmail.com>", 
  "license": "ISC" 
} 

// test/add.spec.js 
... 
describe('Concat Strings', () => { 
  let expected; 
  beforeEach(() => { 
    expected = "Hello"; 
  }); 
   
  afterEach(() => { 
    expected = ""; 
  }); 
   
  it('add Hello + World', () => { 
    expect(add("Hello", "")) 
      .toEqual(expected); 
  }); 
}); 

cd IN_YOUR_NODE_PROJECT 
npm install kwuo -D 

{ 
  ... 
  "scripts": { 
    "test": "kwuo" 
    ... 
  } 
}