Jest/ExpressJS - TypeError: Cannot read properties of undefined - Inner https.request call set to const var - var.on after https call can't be read - express

Question

Can't get the last four lines in the helpers.js below to run for the test. The webpage works great, but I can't get the tests to pass/the mocks correct. This is my first time using Jest and unit testing in general, so there may be a fundamental understanding issue as well.
Function in helpers.js
exports.get_logout = (req, resp) => {
// sent to backend
const options = {
hostname: backend_hostname,
port: backend_port,
method: 'POST',
path: '/api/logout',
ca: ca,
headers: {
'Content-Type': 'application/json',
}
};
// set cookie
options.headers.Cookie = `ws_sid=${req.cookies.ws_sid}`
// send to backend to end session
const https_req = https.request(options, (response) => {
const response_status = response.statusCode;
const response_headers = response.headers;
response.on('data', (d) => {
process.stdout.write(d);
});
response.on('end', () =>{
switch (response_status) {
case 200:
console.log('Successfully logged out')
resp.clearCookie('ws_sid', {path: '/'})
resp.redirect('/')
break;
case 400:
console.log('Error on logout!')
resp.redirect('/');
break;
case 403:
console.log('User not logged in!')
resp.redirect('/');
break;
}
})
});
https_req.on('error', (e) => {
console.error(e);
});
https_req.write(JSON.stringify({}))
https_req.end();
}
the issue in website.test.js, is that the https_req.on is giving a TypeError:Cannot read properties of undefined (reading 'on')
Test here:
const helpers = require('./helpers');
const https = require('node:https');
// Mock for express request parameter
let mockRequest = (sessionData, method, body) => {
return {
session: { data: sessionData, cookie: {_expires: 'test_expire'}},
method: method,
body: {username:"", password:""},
cookies: {ws_sid:""},
};
};
// Mock for express response parameter
let mockResponse = () => {
const res = {};
res.status = jest.fn().mockReturnValue(res);
res.json = jest.fn().mockReturnValue(res);
res.send = jest.fn().mockReturnValue(res);
res.sendStatus = jest.fn().mockReturnValue(res)
res.render = jest.fn().mockReturnValue(res)
res.redirect = jest.fn().mockReturnValue(res)
return res;
};
jest.mock('https');
https.request = jest.fn();
https.on = jest.fn();
https.end = jest.fn();
test('should redirect to / if user successfully logged out', async () => {
const req = mockRequest({ 'username': 'all' });
const resp = mockResponse();
helpers.get_logout(req, resp);
expect(resp.redirect).toHaveBeenCalledWith('/');
});
Any help greatly appreciated.
I have tried mocking the https_req object - but kept getting errors with the implementation (not a function, can't access before initialization). I tried adding the https_req object to the mockRequest with (on, end) but got the same TypeError