Must be coded WITH UNIT TESTING in Scala, we are asked to create a self checkout

Must be coded WITH UNIT TESTING in Scala, we are asked to create a self checkout system with a GUI (included). We just need to code the methods and classes used by the GUI. I have completed 5/6 tasks, I just need the 6th completed. I have provided the code that you will use to finish the project along with the project details.
I need an expert to code Lecture Task 6 along with a new test suite titled LectureTask6 in the tests folder.