I'm creating a problem in Polygon that will include a grader. My grader has several assert statements (and all the testing is done using these assertions). The problem is that contestants can't see the error message if any assertion fails.

Right now the test result shows Runtime Error and the message is "Exit code was 3". And I'd like to make it possible for contestants to see the exact assertion message.

How does one propagate the error message forward to the test results?