如何用 Jest 模拟 uuid [英] How to mock uuid with Jest

问题描述

所以在我寻找问题的答案时，我发现了这篇文章:Jest:如何全局模拟 node-uuid(或任何其他导入模块)

so on my search for an answer to my problem I found this post: Jest: How to globally mock node-uuid (or any other imported module)

我已经尝试过这个答案，但我似乎无法正确使用它，因为它给了我一个未定义的错误.我是测试领域的新手，所以请原谅任何重大错误:

I already tried the answer but I can't seem to use it properly, as it´s giving me an undefined error. I'm new to the testing scene so please excuse any major errors:

这是我的第一个方法

const mockF = jest.mock('uuid'); 

mockF.mockReturnValue('12345789'); 

但它无法识别这些功能.

But it wouldn't recognize the functions.

mockF.mockReturnValue 不是函数"以及我尝试过的其他方法.

"mockF.mockReturnValue is not a function" among others I tried.

然后我尝试按照帖子的建议手动模拟，但似乎无法使其正常工作，你能帮我吗?谢谢

Then I tried to manually mock as the post suggested but can' seem to make it work, can you help me? Thanks

如果有帮助，这里是整个测试:

Here's the entire test if it helps:

    const faker = require('faker');
    const storageUtils = require('../../storage/utils');
    const utils = require('../utils/generateFile');
    const { generateFileName } = storageUtils;
    const { file } = utils;

    test('should return a valid file name when provided the correct information', () => {
        // ARRANGE
        // create a scope
        const scope = {
            type: 'RECRUITER',
            _id: '987654321',
        };
        // establish what the expected name to be returned is
        const expectedName = 'r_987654321_123456789.png';

        jest.mock('uuid/v4', () => () => '123456789');

        // ACTION
        const received = generateFileName(file, scope);

        // ASSERT
        // expect the returned value to equal our expected one
        expect(received).toBe(expectedName);
    });

推荐答案

使用 mockImplementation 模拟它.

import uuid from 'uuid/v4';
jest.mock('uuid/v4');

describe('mock uuid', () => {
  it('should return testid }', () => {
    uuid.mockImplementation(() => 'testid');
    ...
  });  
});

确保您导入 uuid 正确(使用正确的版本参考，例如 v4、v3...)

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