Get last seen even if its not part of statistics (#911)

* Get last seen even if its not part of statistics

* Revert broken part of change

* Only convert last seen to datetime once

* Move where datetime conversion happens

* Small improvement

* Add coverage

* Test last seen in statistics

Author: raman325

test/fixtures/lock_schlage_be469_state.json

@@ -42,6 +42,7 @@
     }
   },
   "label": "BE469",
+  "lastSeen": "2023-07-18T15:42:34.701Z",
   "neighbors": [1, 2, 3, 4, 13],
   "interviewAttempts": 1,
   "endpoints": [

test/model/test_node.py

@@ -189,6 +189,14 @@ def test_from_state(client):
     assert node.last_seen == datetime(2023, 7, 18, 15, 42, 34, 701000, UTC)
 
 
+async def test_last_seen(lock_schlage_be469):
+    """Test last seen property."""
+    assert lock_schlage_be469.last_seen == datetime(
+        2023, 7, 18, 15, 42, 34, 701000, UTC
+    )
+    assert lock_schlage_be469.last_seen == lock_schlage_be469.statistics.last_seen
+
+
 async def test_highest_security_value(lock_schlage_be469, ring_keypad):
     """Test the highest_security_class property."""
     assert lock_schlage_be469.highest_security_class == SecurityClass.S0_LEGACY

zwave_js_server/model/node/__init__.py

@@ -115,6 +115,7 @@ def __init__(self, client: Client, data: NodeDataType) -> None:
             client, data.get("statistics", DEFAULT_NODE_STATISTICS)
         )
         self._firmware_update_progress: NodeFirmwareUpdateProgress | None = None
+        self._last_seen: datetime | None = None
         self.values: dict[str, ConfigurationValue | Value] = {}
         self.endpoints: dict[int, Endpoint] = {}
         self.status_event = asyncio.Event()
@@ -359,9 +360,7 @@ def keep_awake(self) -> bool:
     @property
     def last_seen(self) -> datetime | None:
         """Return when the node was last seen."""
-        if last_seen := self.data.get("lastSeen"):
-            return datetime.fromisoformat(last_seen)
-        return None
+        return self._last_seen
 
     @property
     def default_volume(self) -> int | float | None:
@@ -380,6 +379,10 @@ def update(self, data: NodeDataType) -> None:
         self._statistics = NodeStatistics(
             self.client, self.data.get("statistics", DEFAULT_NODE_STATISTICS)
         )
+        if last_seen := data.get("lastSeen"):
+            self._last_seen = datetime.fromisoformat(last_seen)
+        if not self._statistics.last_seen:
+            self._statistics.last_seen = self.last_seen
 
         new_values_data = {
             _get_value_id_str_from_dict(self, val): val
@@ -1119,5 +1122,5 @@ def handle_statistics_updated(self, event: Event) -> None:
         event.data["statistics_updated"] = self._statistics = NodeStatistics(
             self.client, statistics
         )
-        if last_seen := statistics.get("lastSeen"):
-            self.data["lastSeen"] = last_seen
+        if self._statistics.last_seen:
+            self._last_seen = self._statistics.last_seen