Add tests to the project

[Airthee]

Hi !

I see that the project is not covered by tests, am I missing something ?
I think it would be very important to cover the project with tests.
I know it's a big job, but we need it to stop regressions, improve stability and maintainability.
Tests also help to understand the code (to get more contributors — like me).
Do you need more arguments ?

I volunteer to do it.

I suggest one PR per covered file.
I will be easy for people to help, by commenting on this post wich file they take.

[thornbill]

Yes tests would be great! (You really don't need to convince us. 😉) Unfortunately I think a lot of the legacy code will be virtually impossible to cover with unit tests due to dependencies on side effects. However there has been some movement on a couple different testing initiatives just in the past week!

1. Unit tests:
   • Support for writing tests with vitest is now available.
   • Currently the only test is for cardBuilderUtils
   • It would probably be easiest to start writing tests for the utils files since they should be mostly self contained.
2. End-to-end tests:
   • I started a new repository for adding end-to-end tests.