Question Authors' Forum

The inability to submit just the preloaded answer was introduced for performance reasons. Without that constraint, at the end of a test or exam, all questions with an answer preload would be sent to the jobe server for marking. With large classes this could result in thousands of jobs being thrown at the jobe server within a few seconds, which could overload the server. It's really an extension of the idea that Moodle doesn't grade empty answers - the student has to have done something in order to get graded.

However, I agree that it's a nuisance in your particular use case and I don't have an immediate solution. My only suggestions are that you can tell the students to make a trivial edit, such as adding a space character on the end of a line, or you could paste the results of the initial (disallowed) submit into the question specification with wording like "If the preloaded code were tested, it would fail as follows: ....".

You said that "even trivial changes like adding a blank line have no effect and prevent the tests from being executed."  I think you'll find that's true only if you add whitespace at the end of the answer. Whitespace at the end is trimmed off before comparing the student answer with the preload. But whitespace in the middle of the program should be sufficient to allow grading.

I'm reluctant to further complicate the question authoring UI with yet another checkbox for this particular edge case. But I can look into whether we can enforce the constraint only on quiz submission, and not when Check or Precheck is clicked. That would involve changes to both the CodeRunner plugin and its associated Behaviour plugin.