Unit tests

[mauteri]

Description of the Change

Closes #

How to test the Change

Changelog Entry

Added - New feature
Changed - Existing functionality
Deprecated - Soon-to-be removed feature
Removed - Feature
Fixed - Bug fix
Security - Vulnerability

Credits

Props @username, @username2, ...

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[what-the-diff]

PR Summary

• New Tests Added for RSVP Behavior
  Tests have been added to ensure that the RSVP system behaves correctly when the maximum limit of attendees is set to zero. This helps to ensure the program doesn't allow any attendees when it's not supposed to.

• Assertion Implementation for Waiting List Check
  Assertions have been implemented to ensure that no users remain on the waiting list if the attendance limit is zero. This is to ensure that we don't have any attendees inadvertently left on the waiting list in this situation.

• Confirming Attendee Status
  Additional assertions have been added which confirm that the status of users attending stays the same regardless of the attendance limit. This is to ensure that changing the attendance limit does not unexpectedly change users' status.

• Testing the attending_limit_reached Method
  Tests have been introduced to verify the behavior of the method attending_limit_reached when the maximum limit varies between 0 and 1. This is to ensure that the program correctly detects when the attendance limit has been reached.