Respects returning item to bank in assessment mode for TNL-6753

drag_and_drop_v2/drag_and_drop_v2.py

-# -*- coding: utf-8 -*-
+# -*- coding: utf-8 -*- # pylint: disable=C0302
 #
 """ Drag and Drop v2 XBlock """
 
@@ -694,22 +694,26 @@ class DragAndDropBlock(
             raise JsonHandlerError(409, self.i18n_service.gettext("Max number of attempts reached"))
 
         item = self._get_item_definition(item_attempt['val'])
-
         is_correct = self._is_attempt_correct(item_attempt)
-        # State is always updated in assessment mode to store intermediate item positions
-        self.item_state[str(item['id'])] = self._make_state_from_attempt(item_attempt, is_correct)
-
-        self._publish_item_dropped_event(item_attempt, is_correct)
+        if item_attempt['zone'] is None:
+            del self.item_state[str(item['id'])]
+            self._publish_item_to_bank_event(item['id'], is_correct)
+        else:
+            # State is always updated in assessment mode to store intermediate item positions
+            self.item_state[str(item['id'])] = self._make_state_from_attempt(item_attempt, is_correct)
+            self._publish_item_dropped_event(item_attempt, is_correct)
 
         return {}
 
     def _validate_drop_item(self, item):
         """
-        Validates `drop_item` parameters
+        Validates `drop_item` parameters. Assessment mode allows returning
+        items to the bank, so validation is unnecessary.
         """
-        zone = self._get_zone_by_uid(item['zone'])
-        if not zone:
-            raise JsonHandlerError(400, "Item zone data invalid.")
+        if self.mode != Constants.ASSESSMENT_MODE:
+            zone = self._get_zone_by_uid(item['zone'])
+            if not zone:
+                raise JsonHandlerError(400, "Item zone data invalid.")
 
     @staticmethod
     def _make_state_from_attempt(attempt, correct):
@@ -767,11 +771,31 @@ class DragAndDropBlock(
             'is_correct': is_correct,
         })
 
+    def _publish_item_to_bank_event(self, item_id, is_correct):
+        """
+        Publishes event when item moved back to the bank in assessment mode.
+        """
+        item = self._get_item_definition(item_id)
+
+        item_label = item.get("displayName")
+        if not item_label:
+            item_label = item.get("imageURL")
+
+        self.runtime.publish(self, 'edx.drag_and_drop_v2.item.dropped', {
+            'item': item_label,
+            'item_id': item['id'],
+            'location': 'item bank',
+            'location_id': -1,
+            'is_correct': is_correct,
+        })
+
     def _is_attempt_correct(self, attempt):
         """
         Check if the item was placed correctly.
         """
         correct_zones = self.get_item_zones(attempt['val'])
+        if correct_zones == [] and attempt['zone'] is None and self.mode == Constants.ASSESSMENT_MODE:
+            return True
         return attempt['zone'] in correct_zones
 
     def _expand_static_url(self, url):

drag_and_drop_v2/public/js/drag_and_drop.js

@@ -1162,6 +1162,13 @@ function DragAndDropBlock(runtime, element, configuration) {
                     releaseGrabbedItems();
                     delete state.items[item_id];
                     applyState();
+                    var url = runtime.handlerUrl(element, 'drop_item');
+                    var data = {
+                        val: item_id,
+                        zone: null
+                    };
+
+                    $.post(url, JSON.stringify(data), 'json')
                 }
             });
         }

xblock-sdk @ 0c987356

+Subproject commit 0c987356cba5c5a7d47c98654e030ee4c3cb47c2

tests/unit/test_advanced.py

@@ -859,6 +859,24 @@ class TestDragAndDropAssessmentData(AssessmentModeFixture, unittest.TestCase):
         self._do_attempt()
         self.assertEqual(self.block.raw_earned, expected_score)
 
+    def test_move_item_back_to_bank(self):
+        self.assertFalse(self.block.completed)  # precondition check
+        expected_score = 3.0 / 5.0
+        self._submit_solution({
+            0: self.ZONE_1,
+            1: self.ZONE_2,
+            2: self.ZONE_2,
+            3: self.ZONE_1,
+        })  # would get a 0.8 score
+        self._submit_solution({
+            0: None,
+            1: self.ZONE_2,
+            2: self.ZONE_2,
+            3: self.ZONE_1,
+        })  # will get a 0.6 score
+        self._do_attempt()
+        self.assertEqual(self.block.raw_earned, expected_score)
+
     def test_do_attempt_zero_score_with_all_decoys(self):
         published_grades = []