test(dbus): Add support for testing driver reset notification

Introduce `FakeResetDriverWatchdog` to simulate driver reset triggers.
Update existing tests and add a new test, `test_notify_reset_driver`, to
verify reset notifications using the event signaling mechanism.

tests/dbus_middleware1/process_image/test_interface_picontrol.py

@@ -1,10 +1,13 @@
 # -*- coding: utf-8 -*-
 # SPDX-FileCopyrightText: 2025 KUNBUS GmbH
 # SPDX-License-Identifier: GPL-2.0-or-later
-from revpi_middleware.cli_commands.dbus_helper import BusType, simple_call
+from threading import Thread
+from time import sleep
+
+from revpi_middleware.cli_commands.dbus_helper import BusType, await_signal, simple_call
 from revpi_middleware.dbus_middleware1 import extend_interface
 from tests.dbus_middleware1.bus_provider import TestBusProvider
-from tests.dbus_middleware1.fake_devices import IOCTL_QUEUE
+from tests.dbus_middleware1.fake_devices import IOCTL_QUEUE, RESET_DRIVER_EVENT
 
 
 class TestObjectPicontrol(TestBusProvider):
@@ -20,3 +23,23 @@ class TestObjectPicontrol(TestBusProvider):
         )
         ioctl_call = IOCTL_QUEUE.get(timeout=2.0)
         self.assertEqual((19212, 0), ioctl_call)
+
+    def test_notify_reset_driver(self):
+        timeout = 5
+
+        def target_call_reset_driver():
+            sleep(1.0)
+            RESET_DRIVER_EVENT.set()
+
+        th_wait_for_reset = Thread(target=target_call_reset_driver, daemon=True)
+        th_wait_for_reset.start()
+
+        result = await_signal(
+            "NotifyDriverReset",
+            timeout,
+            extend_interface("picontrol"),
+            bus_type=BusType.SESSION,
+        )
+        self.assertTrue(result)
+
+        th_wait_for_reset.join(timeout=timeout)