Trial and test spaces are sometimes mixed up

See for instance

https://i10git.cs.fau.de/terraneo/hyteg-form-generator/-/blob/master/generate_all_operators.py#L636

and

https://i10git.cs.fau.de/terraneo/hyteg-form-generator/-/blob/master/generate_all_operators.py#L538

but we need to check whether there are more similar issues.