使用 proxyquire 模拟导入有效，但存根函数显示为未调用答案

【问题标题】：Mocking import with proxyquire works but stubbed function shows as not called使用 proxyquire 模拟导入有效，但存根函数显示为未调用
【发布时间】：2020-10-14 18:08:14
【问题描述】：

我有以下测试，我使用 proxyquire 来模拟 nodemailer，并让它的 createTransport 返回一个带有 sendMail 函数的对象，该函数是一个 sinon 存根。

   beforeEach(() => {
        sinonSandbox = createSandbox();
        sendMailMock = sinonSandbox.stub();
        mailService = proxyquire('../src/mailService',
            {
                'node-vault': () => { return { read: () => mockVaultData } },
                'nodemailer': {
                    createTransport: () => {
                        return {
                            sendMail: () => sendMailMock()
                        }
                    }
                }
            }
        )
       
        sinonSandbox.stub(vaultAuthAws.prototype, 'authenticate').returns(Promise.resolve(mockVaultToken));

    });

 afterEach(() => {
        sinonSandbox.restore();
    });


    it('Should call success mail once ', async () => {
        mailService.sendSuccessEmail(userEmail, fileModifiedDate);
        chaiAssert.equal(sendMailMock.called, true);
    });

被测代码：


const getMailerClient = async () => {
    const smtpCreds = await getCredentialsFromVault();
    const transporter = nodemailer.createTransport(
        {
            host: "...",
            port: 2525,
            ssl: true,
            auth: {
                user: smtpCreds.user,
                pass: smtpCreds.password
            },
            tls: {
                minVersion: 'TLSv1.2'
            }
        }
    );
    console.log('TRANSPORTER HERE', JSON.stringify(transporter));
// this prints TRANSPORTER HERE  { sendMail: [Function: sendMail] }

    return transporter
}

 
const sendSuccessEmail = async (userEmail, fileModifiedDate) => {
    const transporter = await getMailerClient();
    console.log("HERE IN SUCCESS", JSON.stringify(transporter));
    // this prints HERE IN SUCCCESS { sendMail: [Function: sendMail] }
    await transporter.sendMail(successMailOptions(userEmail, fileModifiedDate));
}

我很确定正在调用模拟，否则我会得到一个错误，但是当我运行测试时，这就是我得到的：

Should call success mail once :
      AssertionError: expected true to equal false
      + expected - actual

      -true
      +false

      at _callee$ (tests\/mailService.test.js:62:20)
      at tryCatch (node_modules\regenerator-runtime\runtime.js:63:40)
      at Generator.invoke [as _invoke] (node_modules\regenerator-runtime\runtime.js:293:22)
      at Generator.next (node_modules\regenerator-runtime\runtime.js:118:21)
      at asyncGeneratorStep (node_modules\@babel\runtime\helpers\asyncToGenerator.js:3:24)
      at _next (node_modules\@babel\runtime\helpers\asyncToGenerator.js:25:9)
      at C:\Users\ekinw\Projects\manage-gp-output-lambda\node_modules\@babel\runtime\helpers\asyncToGenerator.js:32:7
      at new Promise (<anonymous>)
      at Context.<anonymous> (node_modules\@babel\runtime\helpers\asyncToGenerator.js:21:12)
      at processImmediate (internal/timers.js:456:21)

我们将不胜感激任何和所有的帮助！

【问题讨论】：

标签： node.js unit-testing sinon nodemailer

【解决方案1】：

你不需要proxyquire来做，sinon就够了。

这里是关于如何存根 nodemailer createTransport 以创建虚假 sendMail 函数的示例。

const sinon = require('sinon');
const { expect } = require('chai');
const nodemailer = require('nodemailer');
const mailService = require('./code.js');

describe('TEST', function () {
  const sandbox = sinon.createSandbox();
  // Create fake sendMail variable to evaluate later.
  const fakeSendMail = sandbox.fake();
  // Create stub nodemailer createTransport which return object with fake sendMail.
  const stubCreateTransport = sandbox.stub(nodemailer, 'createTransport').returns({
    sendMail: fakeSendMail,
  });

  it('Should call success mail once ', async function() {
    await mailService.sendSuccessEmail('?', '?');
    expect(stubCreateTransport.called).to.equal(true);
    expect(fakeSendMail.called).to.equal(true);
  });
});

如果我使用您的代码运行上面的测试代码，它会像这样输出。

$ npx mocha code.spec.js 


  TEST
TRANSPORTER HERE {
  sendMail: [Function: fakeInstance] { displayName: 'fake', id: 'fake#0' }
}
HERE IN SUCCESS {
  sendMail: [Function: fakeInstance] { displayName: 'fake', id: 'fake#0' }
}
    ✓ Should call success mail once 


  1 passing (5ms)

注意：

我将console.log('TRANSPORTER HERE', JSON.stringify(transporter)); 更改为console.log('TRANSPORTER HERE', transporter); 进行检查。

【讨论】：