node.js - 用于 NodeJS 单元测试的模拟 AWS 服务

Question

我正在考虑为 NodeJS 项目设置一些单元测试，但我想知道如何模拟我对 AWS 服务的使用情况。我使用的范围很广:SNS、SQS、DynamoDB、S3、ECS、EC2、自动缩放等。有人对我如何模拟这些有任何好的线索吗？

Answer 1

我只是花了几个小时试图让 AWS SQS 模拟工作，没有诉诸导入 aws-sdk 的 aws-sdk-mock 要求> 函数内的客户端。

对 AWS.DynamoDB.DocumentClient 的 mock 非常简单，但是 AWS.SQS 的 mock 让我感到困惑，直到我遇到使用 rewire 的建议。

我的 lambda 将错误消息移至 SQS FailQueue(而不是让 Lambda 失败并将消息返回到常规队列进行重试，然后在 maxRetries 之后返回 DeadLetterQueue)。模拟以下 SQS 方法所需的单元测试:

• SQS.getQueueUrl
• SQS.sendMessage
• SQS.deleteMessage

我将尽力使示例代码保持简洁，同时仍包含所有相关部分:

我的 AWS Lambda (index.js) 的片段:

const AWS = require('aws-sdk');
AWS.config.update({region:'eu-west-1'});
const docClient = new AWS.DynamoDB.DocumentClient();
const sqs = new AWS.SQS({ apiVersion: '2012-11-05' });
// ...snip

删节的 Lambda 事件记录 (event.json)

{
    "valid": {
        "Records": [{
            "messageId": "c292410d-3b27-49ae-8e1f-0eb155f0710b",
            "receiptHandle": "AQEBz5JUoLYsn4dstTAxP7/IF9+T1S994n3FLkMvMmAh1Ut/Elpc0tbNZSaCPYDvP+mBBecVWmAM88SgW7iI8T65Blz3cXshP3keWzCgLCnmkwGvDHBYFVccm93yuMe0i5W02jX0s1LJuNVYI1aVtyz19IbzlVksp+z2RxAX6zMhcTy3VzusIZ6aDORW6yYppIYtKuB2G4Ftf8SE4XPzXo5RCdYirja1aMuh9DluEtSIW+lgDQcHbhIZeJx0eC09KQGJSF2uKk2BqTGvQrknw0EvjNEl6Jv56lWKyFT78K3TLBy2XdGFKQTsSALBNtlwFd8ZzcJoMaUFpbJVkzuLDST1y4nKQi7MK58JMsZ4ujZJnYvKFvgtc6YfWgsEuV0QSL9U5FradtXg4EnaBOnGVTFrbE18DoEuvUUiO7ZQPO9auS4=",
            "body": "{ \"key1\": \"value 1\", \"key2\": \"value 2\", \"key3\": \"value 3\", \"key4\": \"value 4\", \"key5\": \"value 5\" }",
            "attributes": {
                "ApproximateReceiveCount": "1",
                "SentTimestamp": "1536763724607",
                "SenderId": "AROAJAAXYIAN46PWMV46S:steve.goossens@bbc.co.uk",
                "ApproximateFirstReceiveTimestamp": "1536763724618"
            },
            "messageAttributes": {},
            "md5OfBody": "e5b16f3a468e6547785a3454cfb33293",
            "eventSource": "aws:sqs",
            "eventSourceARN": "arn:aws:sqs:eu-west-1:123456789012:sqs-queue-name",
            "awsRegion": "eu-west-1"
        }]
    }
}

精简的单元测试文件(test/index.test.js):

const AWS = require('aws-sdk');
const expect = require('chai').expect;
const LamdbaTester = require('lambda-tester');
const rewire = require('rewire');
const sinon = require('sinon');

const event = require('./event');
const lambda = rewire('../index');

let sinonSandbox;

function mockGoodSqsMove() {
    const promiseStubSqs = sinonSandbox.stub().resolves({});
    const sqsMock = {
        getQueueUrl: () => ({ promise: sinonSandbox.stub().resolves({ QueueUrl: 'queue-url' }) }),
        sendMessage: () => ({ promise: promiseStubSqs }),
        deleteMessage: () => ({ promise: promiseStubSqs })
    }
    lambda.__set__('sqs', sqsMock);
}

describe('handler', function () {
    beforeEach(() => {
        sinonSandbox = sinon.createSandbox();
    });

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

    describe('when SQS message is in dedupe cache', function () {
        beforeEach(() => {
            // mock SQS
            mockGoodSqsMove();
            // mock DynamoDBClient
            const promiseStub = sinonSandbox.stub().resolves({'Item': 'something'});
            sinonSandbox.stub(AWS.DynamoDB.DocumentClient.prototype, 'get').returns({ promise: promiseStub });
        });

        it('should return an error for a duplicate message', function () {
            return LamdbaTester(lambda.handler)
                .event(event.valid)
                .expectReject((err, additional) => {
                    expect(err).to.have.property('message', 'Duplicate message: {"Item":"something"}');
                });
        });
    });
});