Description
Some CodeHarbor tasks might be valid according to the currently supported ActiveRecord validations but invalid according to the ProFormA specification.
One of these examples is a task with a model solution where the model solution does not contain any files. A similar example can be found in openHPI/codeocean#2503 (comment), but for a test without any files (which is valid according to ProFormA). Since #1887 caused another exception (triggered by the invalid ProFormA export), I could not attach a working example directly.
It would be great if tasks in CodeHarbor would be further validated with the ProFormA specification. This could mean we create the XML and use the existing schema validation. However, such an approach might also have a downside, e.g., regarding the performance. Other approaches, like manually adding some of the missing validations, could be explored, too.