Part $2$: Unit testing activity In this part of the coursework, you are to develop a set of unit tests for a scientific calculator program written in JavaScript $($ The output of this part is some source code and a testing report. The source code is provided in a separate ZIP file. Instructions Download the code. At first run the program. Try to use it to calculate some expressions. Then try to understand how does it work. Finally: $*$ Write a total of $9$ tests, organized into three sets. $*$ Each test set should target one functional element of the program $($You cannot choose $+,-,/$ and $*,$ as those have been covered in the course$)*$ Write the code that allows the program to pass your tests. $*$ Explain your approach in each test set. What was your strategy here? $*$ Capture screenshots or console logs of the code before and after it passed the tests, showing the output of the unit testing library. Shorten the output to the most important part, where it lists the number of tests passed and failed. $*$ Write everything up in a report which you should save out to PDF format. $*$copy$/$paste your unit test codes as an appendix in the same PDF as a report Here is a checklist you can use to ensure you have completed all the tasks: