How to create Test Cases in IntelliJ Idea

I am doing competitive programming in JAVA for few months on IntelliJ, but every time I used to enter Test Cases manually for testing my code on sample Test Cases provided. I saw there are few guys who enter and save Test Cases for later. How they do that?

This image shows the popup and option I want, i searched a lot but got no clue where to find this option:

I am using: IntelliJ IDEA 2019.3.4 (Community Edition)