Context

For some projects, it is required to view the front-end test coverage. This PR sets up all the necessary tooling for this.

Changes

• Added: @vitest/coverage and @vitest/ui
• Configured Vitest with some good defaults
• Added: missing unit tests to improve test coverage

Screenshot

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have tested my code for breaking changes and added the corresponding footer in this PR if needed
• I have added tests that prove my fix is effective or that my feature works