Add Unit Tests

[HenriScaff]

As in the screenshot, marking key specifies we use unit tests to test our code. The tests should go in our tests folder. Lab 9 is on testing, so we can perhaps revisit when that's complete?

[jjwilliamjun]

1. Authentication Tests We'll create tests for successful login and signup, as well as handling incorrect credentials and non-existent user scenarios.

2. Drawing Tests We'll test the word generator functionality by ensuring that a new word is provided each time a drawing session starts and check that the timer behaves as expected.

3. Guessing Tests Tests will cover correct guesses, incorrect guesses, and timing functionalities.