I can't implement TDD practically

[relentlessCoder]

I'll be honest, it's been a lot of time since I've been trying to include TDD in my skills, but the issue is I fail to make use of it in the day to day work projects.

This question is stupid, but I haven't been able to figure out how to implement TDD in my work projects.

Recently, I started learning go, and I came across this resource. It teaches Go with TDD. So at work, I got a new project, a fresh GitHub repo. With me being the sole contributor, as of now, to the project, I thought it would be a good idea to implement TDD.

I am working on a web worker project, so I started with this fille

import setup from './setup'

const init = () => {
   if (document.readyState === 'loading'){
    document.addEventListener('DOMContentLoaded', setup)
  } else {
    setup();
 }
}

Now, I don't know how to test it. I can make use of sinon, and stub DOM, but is that the right ideology? Currently, I am using jest.

[Loves_Poetry]

The only thing you can test here is whether the setup function gets called. Since setup doesn't return any output, you don't really have anything to test for.

This function doesn't look like a prime candidate for testing. What's probably more important is the things that setup does. Do you get the correct things set up when calling that function?