emcy: Fix maximum timeout logic errors in EmcyConsumer.wait()

canopen/emcy.py

@@ -72,16 +72,19 @@ def wait(
         while True:
             with self.emcy_received:
                 prev_log_size = len(self.log)
-                self.emcy_received.wait(timeout)
+                remaining = end_time - time.time()
+                if remaining <= 0:
+                    return None  # Actual timeout reached
+                self.emcy_received.wait(remaining)
                 if len(self.log) == prev_log_size:
-                    # Resumed due to timeout
-                    return None
+                    if time.time() >= end_time:
+                        # Resumed due to timeout
+                        return None
+                    else:
+                        continue
                 # Get last logged EMCY
                 emcy = self.log[-1]
                 logger.info("Got %s", emcy)
-                if time.time() > end_time:
-                    # No valid EMCY received on time
-                    return None
                 if emcy_code is None or emcy.code == emcy_code:
                     # This is the one we're interested in
                     return emcy

test/test_emcy.py

@@ -86,6 +86,10 @@ def test_emcy_consumer_wait(self):
         def push_err():
             emcy.on_emcy(0x81, b'\x01\x20\x01\x01\x02\x03\x04\x05', 100)
 
+        def no_err():
+            with emcy.emcy_received:
+                emcy.emcy_received.notify_all()
+
         def check_err(err):
             self.assertIsNotNone(err)
             self.check_error(
@@ -103,6 +107,10 @@ def check_err(err):
         ):
             check_err(emcy.wait(timeout=TIMEOUT))
 
+        # Check unfiltered wait, spurious condition wake-up.
+        with mock_rx_thread(emcy, no_err):
+            self.assertIsNone(emcy.wait(timeout=TIMEOUT))
+
         # Check filtered wait, on success.
         with (
             self.assertLogs(level=logging.INFO),