用Jest单元测试JS脚本：我可以模拟ES6类

Question

when I import a class from a module

const { OAuth2Client } = require('google-auth-library');

How can I mock it ?

jest.mock("google-auth-library");  // not mocking directly OAuth2Client

jest.mock("google-auth-library", OAuth2Client ) // is incorrect

And if I add the online implementation, I don't have the class name

jest.mock("google-auth-library", () => {
   return jest.fn().mockImplementation(() => {
      return {
        setCredentials: setCredentialsMock,
        getAccessToken: getAccessTokenMock
      }
   })
});

so I cannot call the constructor :

const oAuth2Client = new OAuth2Client({...});

Feedback welcome

UPDATE 1 --

Here as the most important coding from google-auth-library-nodejs related to my issue

google-auth-library-nodejs module

======================================= /src/auth/index.ts ... export {.., OAuth2Client,...} from './auth/oauth2client'; ... const auth = new GoogleAuth(); export {auth, GoogleAuth};

    =======================================
    /src/auth/oauth2client.js

    import {AuthClient} from './authclient';
    ...
    export class OAuth2Client extends AuthClient {
      ....
      constructor(clientId?: string, clientSecret?: string, redirectUri?: string);
      constructor(
         ...
        super();
        ...
        this._clientId = opts.clientId;
        this._clientSecret = opts.clientSecret;
        this.redirectUri = opts.redirectUri;
        ...
      }
      ...
      getAccessToken(): Promise<GetAccessTokenResponse>;
      ...
    }

======================================= /src/auth/authclient.ts

    import {Credentials} from './credentials';
    ...
    export abstract class AuthClient extends EventEmitter {
       ...
      setCredentials(credentials: Credentials) {
        this.credentials = credentials;
      }
    }

======================================= /src/auth/credentials.js

    export interface Credentials {
      refresh_token?: string|null;
      expiry_date?: number|null;
      access_token?: string|null;
      token_type?: string|null;
      id_token?: string|null;
    }
    ...

Answer 1

SOLVED ... using the following specs :

jest.mock("google-auth-library");
const { OAuth2Client } = require('google-auth-library');

const setCredentialsMock = jest.fn();
const getAccessTokenMock = jest.fn();

OAuth2Client.mockImplementation(() => {
  return {
    setCredentials: setCredentialsMock,
    getAccessToken: getAccessTokenMock
  }
});

import index from "../index.js"

describe('testing...', () => { 
  it("should setCredentials correctly....", () => {
    // GIVEN
    const oAuth2Client = new OAuth2Client("clientId", "clientSecret", "redirectUri");
    // WHEN
    oAuth2Client.setCredentials({ refresh_token: "aRefreshToken"});
    // THEN
    expect(setCredentialsMock).toHaveBeenCalledWith({ refresh_token: "aRefreshToken" });
  });
});