You are developing a Python application and want to implement unit tests for a function that calculates the factorial of a number. The function is already written, and you want to leverage GitHub Copilot to help you create unit tests for the function. Which of the following steps is the correct approach to generate useful unit tests with GitHub Copilot? def factorial ( n ): if n == 0 : return 1 else : return n * factorial ( n - 1 )