Resolve "Updating own past feedback sets other tutors assignment to is_done=True"

Closes #155 (closed)

core/models/assignment.py

@@ -14,6 +14,10 @@ class DeletionOfDoneAssignmentsNotPermitted(Exception):
     pass
 
 
+class CanOnlyCallFinishOnUnfinishedAssignments(Exception):
+    pass
+
+
 class TutorSubmissionAssignment(models.Model):
 
     assignment_id = models.UUIDField(primary_key=True,
@@ -32,6 +36,20 @@ class TutorSubmissionAssignment(models.Model):
         return (f'{self.subscription.owner} assigned to {self.submission}'
                 f' (done={self.is_done})')
 
+    def finish(self):
+        self.refresh_from_db()
+        if self.is_done:
+            raise CanOnlyCallFinishOnUnfinishedAssignments()
+
+        meta = self.submission.meta
+        # TODO add reviewer final
+        meta.feedback_authors.add(self.subscription.owner)
+        meta.done_assignments += 1
+        meta.has_active_assignment = False
+        self.is_done = True
+        self.save()
+        meta.save()
+
     def delete(self, *args, **kwargs):
         if self.is_done:
             raise DeletionOfDoneAssignmentsNotPermitted()