Add tests for cosmetic objects

Summary

This pull request add tests for all cosmetic objects.

[x] If code changes were made then they have been tested.
- [ ] I have updated the documentation to reflect the changes.
[ ] This PR fixes an issue.
[ ] This PR adds something new (e.g. new method or parameters).
[ ] This PR is a breaking change (e.g. methods or parameters removed/renamed)
[ ] This PR is not a code change (e.g. documentation, README, ...)