Mocking aws-sdk promises with aws-sdk-mock using jest

Question

can you please see below code and tell me what is wrong with it? The code times out after 5 seconds, but I would expect it to run just fine, as per official description.

Does anyone see what is fundamentally wrong?

import * as AWS from "aws-sdk-mock";
import * as _AWS from "aws-sdk"; 

beforeAll(async (done) => {
  //get requires env vars
 });

describe("the module", () => {

  it("should read from the database", async () => {
    AWS.mock('DynamoDB.DocumentClient', 'get', (error, callback) => { callback(null, "got it")});
    expect(await (new _AWS.DynamoDB.DocumentClient()).get({TableName:"", Key: {pk: "foo", sk: "bar"}}).promise()).toBe("got it");
  });
});

afterAll(() => {
  AWS.restore();
});

Answer 1

i finally found the working variant:

import * as AWSMock from "aws-sdk-mock";
import * as AWS from "aws-sdk"; 
import { GetItemInput } from "aws-sdk/clients/dynamodb";

beforeAll(async (done) => {
  //get requires env vars
  done();
 });

describe("the module", () => {

  it("should mock getItem from DynamoDB", async () => {

    AWSMock.setSDKInstance(AWS);
    AWSMock.mock('DynamoDB', 'getItem', (params: GetItemInput, callback: Function) => {
      console.log('DynamoDB', 'getItem', 'mock called');
      callback(null, {pk: "foo", sk: "bar"});
    })

    let input:GetItemInput = { TableName: '', Key: {} };
    const dynamodb = new AWS.DynamoDB({apiVersion: '2012-08-10'});
    expect(await dynamodb.getItem(input).promise()).toStrictEqual( { pk: 'foo', sk: 'bar' });

    AWSMock.restore('DynamoDB');
  });

  it("should mock reading from DocumentClient", async () => {

    AWSMock.setSDKInstance(AWS);
    AWSMock.mock('DynamoDB.DocumentClient', 'get', (params: GetItemInput, callback: Function) => {
      console.log('DynamoDB.DocumentClient', 'get', 'mock called');
      callback(null, {pk: "foo", sk: "bar"});
    })

    let input:GetItemInput = { TableName: '', Key: {} };
    const client = new AWS.DynamoDB.DocumentClient({apiVersion: '2012-08-10'});
    expect(await client.get(input).promise()).toStrictEqual( { pk: 'foo', sk: 'bar' });

    AWSMock.restore('DynamoDB.DocumentClient');
  });
});