You have a buggy-not-runnable-undocumented backend service. It's dead simple, you just have to read the codes very-very carefully.
run nodemon app.js, fix the reported errors. Once it runs properly, your work is half done. The rest depends on how well you test it.
hint: use Postman, Insomnia, curl, etc
after you think that your code is already correct, run the unit testing but dont forget to stop your nodemon first.. cause we use server for chaiHttp.
Don't Edit The Testing!!
Good luck and have fun! 🎉