[FZ Editor] Add unit tests

[enricogior]

Summary of the new feature/enhancement

The new FZ editor does not have any tests. We need to fix that.

[crutkas]

This is still a thing, correct? we only have it for the main FZ looking at this

[Jay-o-Way]

@enricogior i assume this is still need? What test do you think should be added?

[jaimecbernardo]

@SeraphimaZ , do you know the status of this? Do we have editor tests?

[SeraphimaZykova]

@SeraphimaZ , do you know the status of this? Do we have editor tests?

We don't have any.