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Accepted
RoyM
Asked: 2024-02-04 07:23:15 +0800 CST

jest.spyOn 似乎没有正确模拟默认导出函数

  • 772

我似乎无法弄清楚为什么这个测试失败了；我已将问题减少到这两个文件..

[文件：esm-user.js]

const getJack = () => {return 'Jack';};
const getJill = () => {return 'Jill';};
const getUsers = () => {return [getJack(), getJill()];};
export default { getUsers, getJack };

[文件：esm-user-spy.spec.js]

import users from './esm-user';

describe("Mocks and Spies", () => {
  test.only("partial mock (jack)", () => {
    var getJackSpy = jest.spyOn(users, 'getJack').mockReturnValue('Mock Jack');
    expect(users.getUsers()).toEqual(['Mock Jack', 'Jill']);
  });
});

[输出]

expect(received).toEqual(expected) // deep equality
  Array [
-   "Mock Jack",
+   "Jack",
    "Jill",
  ]
unit-testing

1 个回答

  1. Best Answer

    getUsers调用函数声明getJack，但您正在监视getJack默认导出对象的属性，并用您的模拟实现替换默认导出的该键处的值。

    getUsers该文件中的函数不会调用getJack默认导出对象，而是调用getJack文件中的声明。

    例如，下面是一种方法（还有很多其他方法），因为您正在模拟实现的函数与中调用的函数相同getUsers

    // esm-user.js
const internalApi = {
  getJack: () => 'Jack',
  getJill: () => 'Jill',
};

const getUsers = () => {
  return [internalApi.getJack(), internalApi.getJill()];
};

export default { getUsers, internalApi };

    // esm-user-spy.spec.js
import users from '../src/esm-user.js';

describe('Mocks and Spies', () => {
  it.only('partial mock (jack)', () => {
    var getJackSpy = jest
      .spyOn(users.internalApi, 'getJack')
      .mockReturnValue('Mock Jack');
    expect(users.getUsers()).toEqual(['Mock Jack', 'Jill']);
  });
});
    • 1

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