Mocking aws-sdk in jest

mock-aws-sdk.test.js

const AWS = require('aws-sdk');

//In the test file
const mockDynamodbGetItem = jest.fn();
const mockS3GetObject = jest.fn();

//mock aws sdk
jest.mock('aws-sdk', () => {
    return {
        DynamoDB: jest.fn(() => ({
            GetItem: mockDynamodbGetItem
        })),
        S3:jest.fn(()=>({
          GetObject:mockS3GetObject
        }))
    };
});

describe('test', () => {
    beforeEach(() => {
        mockDynamodbGetItem.mockReset();
        mockS3GetObject.mockReset();
    });

    afterEach(() => {
        jest.restoreAllMocks();
    });
    test('it return the item from dynamodb table', async done => {
        mockDynamodbGetItem.mockImplementation((params,callback) => {
            callback(null, { Item: { Uid: { S: 'String' }, EngagementId: { S: 'Number' } } })
            };
        });
        let ClassToTest = new ClassToTest();
        let response = await ClassToTest.functionToTest1()
        expect(response.items.length).toEqual(0);
        done();
    });

    test('it should get the data from s3', async done => {
        mockS3GetObject.mockImplementation((params,callback) => {            
                    callback(null, { Body: "test document" })               
            };
        });
        let ClassToTest = new ClassToTest();
        let response = await ClassToTest.functionToTest2()
        expect(response.Body).toEqual("test document");
        done();
    });
})

//from module to test file
class ClassToTest {
    constructor() {}
    functionToTest1(hashKeyValue,rangeKeyValue) {
        var dynamodb = new AWS.DynamoDB({ apiVersion: '2012-08-10' });
        let params = {
            Key: {
                HashKeyElement: {
                    S: hashKeyValue
                },
                RangeKeyElement: {
                    S: rangeKeyValue
                }
            },
            TableName: 'Table Name here'
        };
        return new Promise((resolve,reject)=>{
            dynamodb.GetItem(params,(err,data)=>{
                if(err){reject(err)}
                resolve(data);
            })
        })
        return dynamodb.GetItem(params).promise();
    }
    functionToTest2() {
        let s3 = new AWS.S3({ apiVersion: '2006-03-01' });
        let params = {
            Bucket: "examplebucket", 
            Key: "SampleFile.txt", 
        }
        return new Promise((resolve,reject)=>{
            s3.getObject(params,(err,data)=>{
                if(err){reject(err)}
                resolve(data)
            })
        })
    }
}