jest always runs the original function even though it’s mocked

We are adding unit tests to our javaScript project and we are using jest for it.
  As I saw online, we can create _mocks_ folder and add different files we want to mock to this folder.
The problem with this approach is that I couldn’t find a way to create dynamic mocks (I want to create different mocks for the same file/class/function).

This is what I tried:
The original class:

const httpClient = {
    get(str){
      return str;
    }
  };

  module.exports = { httpClient }

The mock file in _mocks_ :

const httpClient = {
    get(str){
      return 'a';
    }
  };

  module.exports = { httpClient }

The mock in the test file (named project.test.js):

const { httpClient } = require('./httpClient');
describe('fetchAndProcessUserData', () => {
  jest.mock('httpClient', () => ({
    ...jest.requireActual('./httpClient.js'),
    get: jest.fn().mockImplementation((str) => 'b')
  }));
  it('string should return b', () => {
    const returnValue = httpClient.get('not good');
    
    expect(returnValue).toBe('b');
  });
});

I also tried writing the mock code before the ‘describe’ in the ‘describe’ and in the test itself (the it block)

Some other jest functions I tried:

• get: jest.fn().mockReturnValue(‘return this’)
• get: jest.fn(() => ‘return this’)

For some reason it always run the original get() function and not the mock one.

This is the configuration I’m using, incase it’s any help:

const { defaults } = require('jest-config')

module.exports = {
  ...defaults,
    rootDir: '.',
  
    moduleFileExtensions: ['js', 'json', 'jsx', 'ts', 'tsx', 'node'],
  
    moduleDirectories: ['node_modules'],
    automock: false
  };

I would appreciate any help 🙂