How to mock a ethereum provider for unit testing of REST API with jest?

[vineetaparodkar]

REST API has following basic structure(index.js)where provider, wallets are created using web3HttpProvider and etherjs when server is started.

Index.js

const web3HttpProvider=require("web3-providers-http");
const {ethers}= require ("ethers");

const app= express();
var provider=new web3HttpProvider (url,options);
var deploymentProvider= new ethers.providers.Web3Provider(provider);
Var wallet= new ethers.Wallet(privatekey, deploymentProvider);
var contractInstance= new ethers.Contract(address,abi,wallet);

app.get("/getvalue",async(req,res)=>{
var response=await instance.greeting();
res.status(200).json({response})
});

app.listen(port,()=>{console.log("server listening")});

Solution tried: index.test.js

const web3HttpProvider= require ("web3-providers-http)
jest.mock("web3-providers-http",()=>{
return provider;});

beforeAll(async()=>{
console.log("test:",new web3HttpProvider(url,null));});

Which results in web3HttpProvider is not a constructor. How to properly mock web3HttpProvider and etherjs to write unit test for REST APIs?