开玩笑地模拟“this”对象上的方法

Posted 2023-02-22

【中文标题】开玩笑地模拟“this”对象上的方法

【英文标题】：Mocking a method on "this" object in jest

【发布时间】：2019-12-21 02:31:42

【问题描述】：

我有以下实现：

export const actions = 
  async submitPhoneNumber(context) 
    let data = await this.$axios.
        $get('https://jsonplaceholder.typicode.com/todos/1')
    // do something with data
    return data

  

当我运行测试时，我得到了

TypeError: 无法读取未定义的属性“$get”

如何模拟this.$axios.$get？

我开玩笑地看着嘲笑global，但嘲笑global只是在嘲笑window.whatever。

我需要模拟 this 对象。

这是我的测试：

import  actions  from '@/store/channel-add'
import flushPromises from 'flush-promises'
describe('channel-add', () => 
  it('submits phone number and returns phone code hash', async () => 
    let data = await actions.submitPhoneNumber()
    await flushPromises()

    expect(data).toBeTruthy()
  )
)

【参考方案1】：

解决办法如下：

index.ts:

export const actions = 
  // I don't know where you get $axios from this, you didn't give the completed code. so I made a fake one for the demo.
  $axios: 
    $get: url => ''
  ,
  async submitPhoneNumber(context) 
    let data = await this.$axios.$get('https://jsonplaceholder.typicode.com/todos/1');
    // do something with data

    data = this.processData(data);
    return data;
  ,

  // for demo
  processData(data) 
    return data;
  
;

index.spec.ts:

import  actions  from './';

actions.$axios = 
  $get: jest.fn()
;

describe('actions', () => 
  it('should mock action.$axios.$get method', () => 
    expect(jest.isMockFunction(actions.$axios.$get)).toBeTruthy();
  );
  it('should get data correctly', async () => 
    (actions.$axios.$get as jest.Mock<any, any>).mockResolvedValueOnce( userId: 1 );
    const actualValue = await actions.submitPhoneNumber();
    expect(actualValue).toEqual( userId: 1 );
    expect(actions.$axios.$get).toBeCalledWith('https://jsonplaceholder.typicode.com/todos/1');
  );
);

单元测试结果：

 PASS  src/mock-module/axios/index.spec.ts
  actions
    ✓ should mock action.$axios.$get method (4ms)
    ✓ should get data correctly (4ms)

Test Suites: 1 passed, 1 total
Tests:       2 passed, 2 total
Snapshots:   0 total
Time:        2.181s, estimated 3s