Stubing AWS SQS client

Question

Im trying to stub aws-sdk/client-sqs calls. Im both new to aws and stubbing and I cant find much in the docs to do with stubbing using mocha/chai

My file

import { SQSClient, ReceiveMessageCommand, DeleteMessageCommand } from '@aws-sdk/client-sqs'
const sqsClient = new SQSClient()

const params = {
    AttributeNames: ['SentTimestamp'],
    MaxNumberOfMessages: 10,
    QueueUrl: paymentsUrl,
    //....more params
}

const getPolledMessages = async sqsClient => {

    const data = await sqsClient.send(new ReceiveMessageCommand(params))
    //....continue to do stuff with the data
}

My test is as below. I heavily borrowed from this test which stubs @aws-sdk/client-ses

import { ReceiveMessageCommand, SQSClient } from '@aws-sdk/client-sqs'
import { expect } from 'chai'


describe('mock sqs', () => {
  let stub;
  before(() => {
    stub = sinon.stub(SQSClient.prototype, 'ReceiveMessageCommand')
  })
  after(() => stub.restore())

  it('can send', async () => {
    await SQSClient.send(new ReceiveMessageCommand(params))
    expect(stub.calledOnce).to.be.true
  })
})

Currently getting the following error

 TypeError: Cannot stub non-existent property ReceiveMessageCommand
 at Function.stub (node_modules/sinon/lib/sinon/stub.js:73:15)
 at Sandbox.stub (node_modules/sinon/lib/sinon/sandbox.js:333:37)

Answer 1

You can stub out dependencies with link seams.. We should use proxyquire package to do that.

E.g.

index.ts:

import { SQSClient, ReceiveMessageCommand } from '@aws-sdk/client-sqs';
const sqsClient = new SQSClient({ region: 'REGION' });

const params = {
  AttributeNames: ['SentTimestamp'],
  MaxNumberOfMessages: 10,
  QueueUrl: 'paymentsUrl',
};

export const getPolledMessages = async () => {
  const data = await sqsClient.send(new ReceiveMessageCommand(params));
};

index.test.ts:

import proxyquire from 'proxyquire';
import sinon from 'sinon';

describe('68017252', () => {
  it('should pass', async () => {
    const sqsClientInstance = {
      send: sinon.stub(),
    };
    const SQSClient = sinon.stub().returns(sqsClientInstance);
    const ReceiveMessageCommand = sinon.stub();
    const { getPolledMessages } = proxyquire('./', {
      '@aws-sdk/client-sqs': {
        SQSClient,
        ReceiveMessageCommand,
      },
    });
    await getPolledMessages();
    sinon.assert.calledWithExactly(SQSClient, { region: 'REGION' });
    sinon.assert.calledOnce(sqsClientInstance.send);
    sinon.assert.calledWithExactly(ReceiveMessageCommand, {
      AttributeNames: ['SentTimestamp'],
      MaxNumberOfMessages: 10,
      QueueUrl: 'paymentsUrl',
    });
  });
});

test result:

  68017252
    ✓ should pass (3331ms)


  1 passing (3s)

----------|---------|----------|---------|---------|-------------------
File      | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s 
----------|---------|----------|---------|---------|-------------------
All files |     100 |      100 |     100 |     100 |                   
 index.ts |     100 |      100 |     100 |     100 |                   
----------|---------|----------|---------|---------|-------------------