How does a student submit an assessment?
Technically, all student submissions are always "accepted", regardless of test case status. Or rather, there is actually no concept of a submission being "accepted".
The only requirement is that the student has made a Marking attempt. What Grok returns to the course tutors (in the submission export) is the latest Marked submission* from each student. We recommend advising your students to Mark their final piece of code to ensure this is the version that is assessed.
So even if a student doesn't pass the Validate test cases, a tutor will still be able to see the submission and assess it.
This is functionally the same as a written assignment where a student can make many attempts and then the one they "hand in" is the one that you assess. On Grok, the latest Marked submission is the one that is "handed in". (Yes, even if they had a "better" solution earlier....this would be equivalent to having the right answer on a paper assignment, crossing it out, and writing a wrong answer.)
* Tutors receive "the latest Marked submission" is broadly true. For more details about precisely what is exported to tutors, please refer to How do I mark student work on Grok?