如何在 Jest Node JS 中测试 AWS 内置方法中使用的 .promise() 方法

Question

我想对此进行完整的单元测试，下面给出了我的函数的代码

function.js

async function sesSendEmail(message) {
var ses = new aws.SES({ apiVersion: "2020-12-01" });
var params = {
    Source: "abc@gmail.com",
    Template: "deviceUsageStatisticsEmailTemplate",
    Destination: {
        ToAddresses: ["xyz@gmail.com"]
    },
    TemplateData: message,
}
try {
    let res = await ses.sendTemplatedEmail(params).promise()
    console.log(res)
}
catch (err) {
    console.log(err)
}

到目前为止我在测试中尝试过的内容：

function.test.js

test('should send templated email success', async () => {
        jest.spyOn(console, 'log');
        const mData = {};
        ses.sendTemplatedEmail.mockImplementationOnce(async (params,callback) => {
            callback(null,mData)
        });
        const message = 'mock message';
        await index.sesSendEmail(message);
        expect(aws.SES).toBeCalledWith({ apiVersion: '2020-12-01' });
        expect(ses.sendTemplatedEmail).toBeCalledWith(
            {
                Source: 'abc@gmail.com',
                Template: 'deviceUsageStatisticsEmailTemplate',
                Destination: {
                    ToAddresses: ['xyz@gmail.com'],
                },
                TemplateData: message,
            },
        );
    await expect(console.log).toBeCalledWith(mData);
    });

    test('should handle error', () => {
        const arb = "network error"
        ses.sendTemplatedEmail = jest.fn().mockImplementation(() => {
            throw new Error(arb);
        })
        const message = 'mock message'
        expect(() => { index.sesSendEmail(message) }).toThrow(arb);
    });
});

问题：

报错

 expect(jest.fn()).toBeCalledWith(...expected)

- Expected
+ Received

- Object {}
+ [TypeError: ses.sendTemplatedEmail(...).promise is not a function],

我尝试了模拟实现的变体，但无济于事。非常感谢 help/suggestion:)

更新

尝试要求 aws-sdk-mock

aws.mock('ses','sendTemplatedEmail',function(callback){callback(null,mData)})

但仍然出现错误

TypeError: Cannot stub non-existent own property ses

Answer 1

我会说模拟 aws sdk 本身并按照您通常的方式测试您的方法。一旦这样的库是 aws-sdk-mock (https://www.npmjs.com/package/aws-sdk-mock)

像这样

const sinon = require("sinon");
const AWS = require("aws-sdk-mock");

test("should send templated email success", async () => {
  const sendEmailStub = sinon.stub().resolves("resolved");
  AWS.mock("SES", "sendTemplatedEmail", sendEmailStub);
  const response = await sesSendEmail("{\"hi\": \"bye\"}");
  expect(sendEmailStub.calledOnce).toEqual(true);
  expect(sendEmailStub.calledWith(
    {
      "Source": "abc@gmail.com",
      "Template": "deviceUsageStatisticsEmailTemplate",
      "Destination": {
        "ToAddresses": ["xyz@gmail.com"]
      },
      "TemplateData": "{\"hi\": \"bye\"}"
    })).toEqual(true);
    expect(response).toEqual("resolved");
    AWS.restore();
});

test("should send templated email failure", async () => {
  const sendEmailStubError = sinon.stub().rejects("rejected");
  AWS.mock("SES", "sendTemplatedEmail", sendEmailStubError);
  const response = await sesSendEmail("{\"hi\": \"bye\"}");
  expect(sendEmailStubError.calledOnce).toEqual(true);
  expect(sendEmailStubError.calledWith(
    {
      "Source": "abc@gmail.com",
      "Template": "deviceUsageStatisticsEmailTemplate",
      "Destination": {
        "ToAddresses": ["xyz@gmail.com"]
      },
      "TemplateData": "{\"hi\": \"bye\"}"
    })).toEqual(true);
    expect(response.name).toEqual("rejected");
    AWS.restore();
});

确保从您的原始方法返回响应和错误。

Answer 2

TypeError: ses.sendTemplatedEmail(...).promise is not a function 表示它期望调用 ses.sendTemplatedEmail() 的结果是一个对象，该对象具有名为 promise.

的函数属性

要解决此问题，您将需要 return 模拟实现中的对象具有预期的 promise 属性。您还需要从模拟实现中删除 async 关键字，因为那样会 return 一个 Promise 对象，而不是具有 promise 属性.

的预期对象

这里是一个示例，它也 returns 来自 .promise() 的 Promise 对象，正如 sendTemplatedEmail.promise() 的生产实施所期望的那样：

ses.sendTemplatedEmail.mockImplementationOnce((params,callback) => ({
  promise: () => Promise.resolve(callback(null,mData)),
}));

如何在 Jest Node JS 中测试 AWS 内置方法中使用的 .promise() 方法

How to test .promise() methods used in AWS built in methods in jest Node JS

javascript

node.js

amazon-web-services

jestjs

async.js