Test not showing when despite inclusion in source

I am working on the random quote project, using react handle the markup.

I am having a problem displaying the test suite despite its inclusion in my source. When I comment out my Javascript code, the test suite appears as expected, but I don’t know what is causing it to dissappear.

My codepen for this project: https://codepen.io/neenjaw/pen/xxwyVLr

I found my problem, I was using the body tag as the entry point for the react app, so it was replacing the contents with the app including the test framework.

Before

const element = <Container />;
const body = document.body;
ReactDOM.render(element, body);

After

const element = <Container />;
const app = document.getElementById('app');
ReactDOM.render(element, app);