jest

mock function，判断被调用次数、参数

const abort = jest.fn()
...
expect((abort as jest.Mock).mock.calls.length).toBe(1)
// 第一次调用的第一个参数
expect((abort as jest.Mock).mock.calls[0][0]).toBe(arg1)

mock function, 设置返回数据

const connect = jest.fn()
(connect as jest.Mock).mockReturnValue('success')

mock object

const aObject = {} as any

mock 3p module

import { axios } from 'axios'
jest.mock('axios')

describe('basic', ()=>{
  beforeEach(()=>{
    // 执行每个单元测试前，清除 getLog 调用信息
    (axios.request as jest.Mock).mockClear()
  })

  it('case1', ()=>{
    (axios.request as jest.Mock).mockReturnValue({...})
  })
})

mock local function & class

import { IntClusterRebalancer } from '../src/int-cluster-rebalancer'
let fn1
jest.mock('../src/int-cluster-rebalancer', () => {
  fn1 = jest.fn()
  return {
    functionName: fn1,
    IntClusterRebalancer: jest.fn().mockImplementation(() => {
      return { rebalance: jest.fn() }
    }),
  }
})

describe('basic', () => {

  beforeEach(() => {
    ;(IntClusterRebalancer as jest.Mock).mockClear()
  })

  it('case1', ()=>{
    const rebalancer = new IntClusterRebalancer()
    // or 任何内部执行 new IntClusterRebalancer() 的方法/对象
    const manager = new Manager() // Manager 内部会执行 new IntClusterRebalancer()
  })
})