fix backend listener

src/operator/backend_listener.py

@@ -930,7 +930,7 @@ def calculate_pod_status(pod: Any) -> Tuple[task.TaskGroupStatus, str, Optional[
                     # When a container fails to create, the pod will not be Ready.
                     # The lastTransitionTime of this condition is the closest timestamp.
                     if condition.type == 'Ready' and condition.status == 'False':
-                        now = datetime.datetime.now()
+                        now = datetime.datetime.now(datetime.timezone.utc)
                         last_transition_time = condition.last_transition_time
                         if last_transition_time:
                             time_diff = now - last_transition_time

src/operator/tests/test_pod_status_calculator.py

@@ -34,18 +34,19 @@
 
 
 def parse_time_string(time_str: str) -> datetime.datetime:
-    """Parse time strings like 'now', 'now-5m', 'now-15m' into datetime objects"""
+    """Parse time strings like 'now', 'now-5m', 'now-15m' into timezone-aware UTC datetimes."""
+    utc_now = datetime.datetime.now(datetime.timezone.utc)
     if time_str == 'now':
-        return datetime.datetime.now()
+        return utc_now
     elif time_str.startswith('now-'):
         parts = time_str[4:]
         if parts.endswith('m'):
             minutes = int(parts[:-1])
-            return datetime.datetime.now() - datetime.timedelta(minutes=minutes)
+            return utc_now - datetime.timedelta(minutes=minutes)
         elif parts.endswith('h'):
             hours = int(parts[:-1])
-            return datetime.datetime.now() - datetime.timedelta(hours=hours)
-    return datetime.datetime.now()
+            return utc_now - datetime.timedelta(hours=hours)
+    return utc_now
 
 
 def create_pod_from_json(test_input: Dict) -> V1Pod: