Adding the test for assessing cancelled sub.

Minor code refactoring.

TNL-900

openassessment/assessment/api/peer.py

@@ -956,8 +956,8 @@ def cancel_submission_peer_workflow(submission_uuid, comments, cancelled_by_id):
 
     Args:
         submission_uuid (str): The UUID of the peer workflow's submission.
-        comments: The reason for cancellation.
-        cancelled_by_id: The ID of the user who cancelled the peer workflow.
+        comments (str): The reason for cancellation.
+        cancelled_by_id (str): The ID of the user who cancelled the peer workflow.
     """
     try:
         workflow = PeerWorkflow.objects.get(submission_uuid=submission_uuid)
@@ -983,14 +983,8 @@ def get_submission_cancellation(submission_uuid):
         submission_uuid (str): The UUID of the peer workflow's submission.
     """
     try:
-        workflow = PeerWorkflow.objects.get(submission_uuid=submission_uuid)
-        workflow_cancellation = workflow.cancellations.latest('created_at')
-        return PeerWorkflowCancellationSerializer(workflow_cancellation).data
-    except (
-        PeerWorkflow.DoesNotExist,
-        PeerWorkflowCancellation.DoesNotExist,
-    ):
-        return None
+        workflow_cancellation = PeerWorkflowCancellation.get_latest_workflow_cancellation(submission_uuid=submission_uuid)
+        return PeerWorkflowCancellationSerializer(workflow_cancellation).data if workflow_cancellation else None
     except DatabaseError:
         error_message = u"Error finding peer workflow cancellation for submission UUID {}.".format(submission_uuid)
         logger.exception(error_message)

openassessment/assessment/models/peer.py

@@ -521,3 +521,17 @@ class PeerWorkflowCancellation(models.Model):
             'cancelled_by_id': cancelled_by_id,
         }
         return cls.objects.create(**cancellation_params)
+
+    @classmethod
+    def get_latest_workflow_cancellation(cls, submission_uuid):
+        """
+        Get the latest PeerWorkflowCancellation for a submission's workflow.
+
+        Args:
+            submission_uuid (str): The UUID of the peer workflow's submission.
+
+        Returns:
+            PeerWorkflowCancellation or None
+        """
+        workflow_cancellations = cls.objects.filter(workflow__submission_uuid=submission_uuid).order_by("-created_at")
+        return workflow_cancellations[0] if workflow_cancellations.exists() else None

openassessment/assessment/test/test_peer.py

@@ -893,6 +893,47 @@ class TestPeerApi(CacheResetTest):
         item = buffy_workflow.find_active_assessments()
         self.assertIsNone(item)
 
+    @raises(peer_api.PeerAssessmentWorkflowError)
+    def test_assess_the_cancelled_submission(self):
+        # This will assess the pulled out submission to assess.
+        buffy_sub, buffy = self._create_student_and_submission("Buffy", "Buffy's answer")
+        xander_sub, xander = self._create_student_and_submission("Xander", "Xander's answer")
+
+        # Check for a workflow for Buffy.
+        buffy_workflow = PeerWorkflow.get_by_submission_uuid(buffy_sub['uuid'])
+        self.assertIsNotNone(buffy_workflow)
+
+        # Buffy is going to review Xander's submission, so create a workflow
+        # item for Buffy.
+        PeerWorkflow.create_item(buffy_workflow, xander_sub["uuid"])
+
+        # Check to see if Buffy is actively reviewing Xander's submission.
+        item = buffy_workflow.find_active_assessments()
+        self.assertEqual(xander_sub["uuid"], item.submission_uuid)
+
+        # Cancel the Xander's submission.
+        xander_workflow = PeerWorkflow.get_by_submission_uuid(xander_sub['uuid'])
+        PeerWorkflowCancellation.create(
+            workflow=xander_workflow, comments='Cancellation reason', cancelled_by_id=buffy['student_id']
+        )
+
+        # Check to see if Buffy is actively reviewing Xander's submission.
+        # She isn't able to get the submission to assess.
+        item = buffy_workflow.find_active_assessments()
+        self.assertIsNone(item)
+
+        # Try to assess the cancelled submission
+        # This will raise PeerAssessmentWorkflowError
+        peer_api.create_assessment(
+            buffy_sub['uuid'],
+            buffy["student_id"],
+            ASSESSMENT_DICT['options_selected'],
+            ASSESSMENT_DICT['criterion_feedback'],
+            ASSESSMENT_DICT['overall_feedback'],
+            RUBRIC_DICT,
+            REQUIRED_GRADED_BY,
+        )
+
     def test_get_workflow_by_uuid(self):
         buffy_answer, _ = self._create_student_and_submission("Buffy", "Buffy's answer")
         self._create_student_and_submission("Xander", "Xander's answer")