Sorry, but that’s the way the grader works: if you get any kind of exception thrown during the execution of any of the tests, then you end up with 0 points for everything. The problem is that the grader can’t complete its execution because of the exception (the assertion that “threw” in your case). Yes, they probably could have written the grader to be able to “catch” exceptions, but they didn’t and we just have to live with it.
So the solution is to figure out why that assertion is failing. Let me reply on the other thread that you started about the issues with your assignment.