Report

Changes made during refactoring:

• Refactored Database and UserManager. Separated responsibilites, user manager now will manage everything user related, and database's functionality is strictly saving and getting users.
• UserManager now depends on Database for saving users to the simulated "database" I created.
• Created both authenticate and authenticateUser. authenticateUser verifies that the id matches and we return true if the email and password matches, this helps to verify if the id matches the email and password, for testing non-existing users. authenticate was first created as a simple way of verifying that both the email and password of the user were correct.

Adhere to SOLID principles:

• register 's only responsibility is registering, separation of responsibilities in the functions, while authenticateUser's only responsiblity is verifying that the id matches to the email and password of said user.
• Database can be extended if needed, based on its current simple functionality later on we can add more queries or features.

The refactoring significantly improved the maintainability and readability of the UserManager and Database classes. Adhering to SOLID principles makes the refactored code now more modular and testable. We can accomodate future requirements with minimal effort.