Allow files to be uploaded alongside a test report

- Attach the file to the stock item
- Link the uploaded attachment to the test report

InvenTree/stock/serializers.py

@@ -212,6 +212,7 @@ class StockItemAttachmentSerializer(InvenTreeModelSerializer):
             'stock_item',
             'attachment',
             'comment',
+            'date',
             'user',
             'user_detail',
         ]
@@ -235,6 +236,14 @@ class StockItemTestResultSerializer(InvenTreeModelSerializer):
             'date'
         ]
 
+        read_only_fields = [
+            'pk',
+            'stock_item',
+            'attachment',
+            'user',
+            'date',
+        ]
+
 
 class StockTrackingSerializer(InvenTreeModelSerializer):
     """ Serializer for StockItemTracking model """