feat: add watchdog for serial when no data received after 5 seconds

Author: horw

pytest-embedded-serial/pytest_embedded_serial/serial.py

@@ -179,6 +179,7 @@ def _event_loop(self):
         defined in _forward_io. The pyserial.Serial methods are mocked to send an event to the queue, and the real
         method is running here.
         """
+        last_data_time = time.time()
         while True:
             try:
                 _e = self._event_q.get_nowait()
@@ -188,11 +189,18 @@ def _event_loop(self):
                 return
 
             if _e == 'read':
+                if time.time() - last_data_time > 5.0:
+                    logging.warning('No data received from serial port for over 5 seconds.')
+                    last_data_time = time.time()
+
                 if self._block_reading:
                     continue
 
                 try:
                     s = self._s.read_all()
+                    if s:
+                        last_data_time = time.time()
+
                     self._q.put(s)
                 except OSError:
                     return