Handin grading without using server?

Basically, I've got a bunch of students submitting assignments, so I get a .zip file from Moodle with a bunch of folders, each of which has one .rkt file.

I've seen that the handin server has really nice tools for defining test suites/checkers for grading student assignments.

I'm wondering if there's a way to use the grading facilities locally, without using the server part of the handin tool? Once I've defined a checker, is there a way to pass it a Racket file directly and have it generate a grading report?

I'll send you the tool that I use for grading. It's a GUI that looks something like DrRacket. There's a list of student submissions on the left, and selecting a submission shows the code starts running tests so you can see the output. So, probably not quite what you had in mind, but maybe useful.

Can you open source it?

In case this is useful: I have in the past used the handin server locally; specifically, I've started a handin server running on my own machine, and then used scripts that make local connections to the handin-server, run the tests, then copy the results back to a given directory. Let me know if you have any interest in seeing this code.