Fix D-Bus enum type conversions for NetworkManager (#6325)

Co-authored-by: Claude <noreply@anthropic.com>

tests/dbus/network/test_interface.py

@@ -184,3 +184,20 @@ async def test_interface_becomes_unmanaged(
     assert wireless.is_connected is False
     assert eth0.connection is None
     assert connection.is_connected is False
+
+
+async def test_unknown_device_type(
+    device_eth0_service: DeviceService, dbus_session_bus: MessageBus
+):
+    """Test unknown device types are handled gracefully."""
+    interface = NetworkInterface("/org/freedesktop/NetworkManager/Devices/1")
+    await interface.connect(dbus_session_bus)
+
+    # Emit an unknown device type (e.g., 1000 which doesn't exist in the enum)
+    device_eth0_service.emit_properties_changed({"DeviceType": 1000})
+    await device_eth0_service.ping()
+
+    # Should return UNKNOWN instead of crashing
+    assert interface.type == DeviceType.UNKNOWN
+    # Wireless should be None since it's not a wireless device
+    assert interface.wireless is None