How to perform a unit and integration test on a website

I want to develop a web application according to the agile method for my college project.We are supposed to release a part of our project at the end of each sprint.According to the guidelines given by our lecturers, we perform unit and integration testing before releasing our module at the end of the sprint.I have no idea how to perform unit and integration tests on a web application. I search the web and read few similar questions have asked on the Stack Overflow as well.But I couldn't get solved my doubt. Can anyone point me out how to perform unit and integration tests on a web application, please?

My website is supposed to register users and let them to log in to the site and to allow them to upload audios and videos.Others can view them and comment on those videos and audios.I am going to develop my site using bootstrap and CodeIgniter frame work. I use MySQL as the database. But I am going to save my videos on the Youtube and to display them on my website using tag.I use my database only to store audios and user details.

Is there any software or framework to perform these two tests?