javascript - JEST 错误 TypeError : specificMockImpl. apply is not a function

Question

尝试使用来自 api 的回调来模拟其中一个函数并得到错误 TypeError: specificMockImpl.apply is not a function

import { IEnvironmentMap, load } from 'dotenv-extended';
import { getTokensWithAuthCode, sdk } from '../src/connection-manager';

describe('getTokensWithAuthCode function Tests', () => {

    jest.useFakeTimers();
    let boxConfig: IEnvironmentMap;

    beforeAll(() => {
        boxConfig = load({
            errorOnMissing: true,
        });
    });

    it('should reject a promise if there is wrong auth code provided', async () => {

        sdk.getTokensAuthorizationCodeGrant = jest.fn().mockImplementation(boxConfig.BOX_AUTH_CODE, null, cb => {
            cb('Error', null);
        });

        try {
            const tokens = await getTokensWithAuthCode();
        } catch (error) {
            expect(error).toBe('Error');
        }
    });
});

我正在尝试测试的功能如下:

import * as BoxSDK from 'box-node-sdk';
import { IEnvironmentMap, load } from 'dotenv-extended';
import {ITokenInfo} from '../typings/box-node-sdk';

const boxConfig: IEnvironmentMap = load({
    errorOnMissing: true,
});

export const sdk: BoxSDK = new BoxSDK({
    clientID: boxConfig.BOX_CLIENT_ID,
    clientSecret: boxConfig.BOX_CLIENT_SECRET,
});

/**
 * - Use the provided AUTH_CODE to get the tokens (access + refresh)
 * - Handle saving to local file if no external storage is provided.
 */
export async function getTokensWithAuthCode() {

    return new Promise((resolve: (tokenInfo: ITokenInfo) => void, reject: (err: Error) => void) => {

        if (boxConfig.BOX_AUTH_CODE === '') {
            reject(new Error('No Auth Code provided. Please provide auth code as env variable.'));
        }

        sdk.getTokensAuthorizationCodeGrant(boxConfig.BOX_AUTH_CODE, null, (err: Error, tokenInfo: ITokenInfo) => {
            if (err !== null) {
                reject(err);
            }

            resolve(tokenInfo);
        });
    });
}

有没有其他方法可以在 Jest 中模拟函数？我看过一篇文章https://www.zhubert.com/blog/2017/04/12/testing-with-jest/

Answer 1

在这一行中，不是将函数传递给 mockImplementation，而是传递三个参数:

jest.fn().mockImplementation(boxConfig.BOX_AUTH_CODE, null, cb => {
  cb('Error', null);
});

看起来您可能刚刚错过了一些牙套。尝试将其切换为:

jest.fn().mockImplementation((boxConfig.BOX_AUTH_CODE, null, cb) => {
  cb('Error', null);
});