A little new the JS and trying to test a function that I made using sinon. For my current setup I have a util.js

const { v4: uuidv4 } = require("uuid");

function generateUUID () {
    return uuidv4();
}

module.exports = { generateUUID }

a dynamo.js helper file

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

async function doesVarExist(var){
  //call to dynamo table to check if an obj exists. Returns a bool value
}

module.exports = { doesVarExist }

and createObject.js file

const util = require("./util");
const dynamo = require("./dynamo");


class CustomObj {
    constructor(uuid, variable1, variable2) {
        this.uuid = uuid;
        this.var1 = variable1;
        this.var2 = variable2;
    }
}

async function createObject(var1, var2) {
  
  if(dynamo.doesVarExist(var1)) {
      const newObj = new CustomObj(
            util.generateUUID(),
            var1,
            var2
            );
  }
  return newObj;
}

module.exports = { CustomObj, createObject }

In the test itself, I’m attempting to stub both the doesVarExist method and the generateUUID method but for some reason, the sinon stub seems to be ignored.
createObject.test.js

const chai = require("chai");
const { expect } = require("chai");
const chaiAsPromised = require("chai-as-promised");
const sinon = require("sinon");
const rewire = require("rewire");

const dynamo = rewire("../../src/dynamo");
const createCustomObjects = rewire("../../src/createObject");
const util = require("../../src/util");

chai.use(chaiAsPromised);
describe("generate object and metadata", () => {
   afterEach(() => {
      sinon.restore();
   });

   it("createObject", async () => {
      sinon.stub(util, "generateUUID").returns("Random1234");

      let objExistStub = sinon.stub(dynamo, "doesVarExist").returns(false);
      createCustomObjects.__set__("doesVarExist", objExistStub);

      const expected = //created expected object here

      const result = await createCustomObjects.createObject("random1", "random2");
      expect(result).to.deep.equal(expected);

   });
});

However what ends up happening is that the doesVarExist function actually does try to make the dynamo call, which then times out. When I tried removing the doesVarExist function call in the code, the generateUUID function also does not work and gives me a random one instead of the seeded value. Any help is appreciated!