REF: Make duration a property of AbstractQuestion

django_twined/admin/admin.py

@@ -131,15 +131,6 @@ def result(obj):
         """
         return obj.result.data
 
-    @staticmethod
-    def duration(obj):
-        """Show the time it took to answer the question in seconds.
-
-        :return int|None:
-        """
-        if obj.answered and obj.asked:
-            return (obj.answered - obj.asked).seconds
-
     def ask_question(self, obj):
         """Override this to ask a question using an async task queue or other method. This will ask the question directly."""
         obj.ask()

django_twined/models/questions.py

@@ -60,6 +60,15 @@ def status_message(self):
         """
         return STATUS_MESSAGE_MAP[self.status]
 
+    @property
+    def duration(self):
+        """Show the time it took to answer the question in seconds.
+
+        :return int|None:
+        """
+        if self.answered and self.asked:
+            return (self.answered - self.asked).seconds
+
     def get_duplicate(self, save=True):
         """Duplicate the question instance and optionally save to the database"""
         kwargs = {}

tests/test_models/test_questions.py

@@ -2,7 +2,9 @@
 # pylint: disable=missing-docstring
 # pylint: disable=protected-access
 # pylint: disable=too-many-public-methods
+import datetime
 import os
+import time
 from unittest import skipIf
 from unittest.mock import patch
 
@@ -18,6 +20,12 @@
 
 
 class QuestionTestCase(TestCase):
+    def test_unasked_question_duration(self):
+        """Test that the duration of an unasked question is `None`."""
+        sr = ServiceRevision.objects.create(name="test-service")
+        q = QuestionWithValuesDatabaseStorage.objects.create(service_revision=sr)
+        self.assertIsNone(q.duration)
+
     @patch("django_twined.models.ServiceRevision.ask", return_value=("subscription", "question_uuid"))
     def test_ask_question(self, mock):
         """Ensures that a question can be asked"""
@@ -32,6 +40,21 @@ def test_ask_question(self, mock):
         self.assertIn("input_manifest", mock.call_args.kwargs)
         self.assertIn("question_attribute", mock.call_args.kwargs["input_values"])
 
+        # Check that the duration is `None` as the question hasn't been answered.
+        self.assertIsNone(q.duration)
+
+    @patch("django_twined.models.ServiceRevision.ask", return_value=("subscription", "question_uuid"))
+    def test_answered_question_duration(self, mock):
+        """Test that the duration of an answered question is a non-zero integer."""
+        sr = ServiceRevision.objects.create(name="test-service")
+        q = QuestionWithValuesDatabaseStorage.objects.create(service_revision=sr)
+        q.input_values = {"question_attribute": "1"}
+        q.ask()
+
+        time.sleep(1)
+        q.answered = datetime.datetime.now(tz=datetime.timezone.utc)
+        self.assertTrue(q.duration > 0)
+
     def test_input_values_get_saved(self):
         """Ensures that input values get saved on the mixin.
         I'm testing this because the objects.create() doesn't accept the input_values