Improve mutation testing score

[Chemaclass]

📚 Description

You can run infection to realize that the score is far away from 100% which is the desired state.

composer infection

What is Mutation Testing? https://infection.github.io/guide/ (@infection)

🥇 Goal

Create small PRs improving the test/prod code to reach the 100% mutation testing score.

Note: This is labeled as a "Good first issue" because it aims to create visibility, so you can fix whatever little error/warning and create a PR with that fix. The idea is to improve the score one PR at a time, not all changes in one unique PR 😉

[Mohammed-Alama]

This is the first time to learned about Mutation testing and it impressed me
I think I can take this over