I've tried a couple of approaches but I'm not sure if it's possible to mock a nested function in Jest. I read the official docs where they use axios, but I'm trying to mock a function that is imported, not a module.

for example, I have some function A, and within A I call B. I want to mock B so that it returns true once and then false once.

B is a function I imported that I wrote in another file, and I'm testing A.

so far I have tried to import function B into my test file and create a mock of it, but I don't think it's working how I thought it would

for example I have tried this

import { b } from "../util"
jest.mock("b", () => jest.fn().mockReturnValue(true));

and then my tested file would be

function a() => {
  while b() {
    do something;
  }
}

should I rewrite my test or function I'm testing?