General Question about the Testing Challenges in the Information Security And Quality Assurance Certification

So I was introduced to Chai and Mocha for the very first time, was not able to understand them just by looking at the exercises, looked for this on the web, so I solved some exercises for Chai, which do not look so difficult, however I have a question about it, I just wanted to be sure that the exercises which I am solving are just to understand the different functions in the chai.assert library, because the test’s readily have values entered and are not testing any functions from the web application. or is it that I have a wrong idea about the exercises and am missing something ?

Completed all the exercises and understood that the whole point of the web app was for the functional tests, although they were just using Chai and not mocha, guess I need to look where was Mocha and Chai being used together