add subtest for timeout exception

Author: vladak

tests/test_recv_timeout.py

@@ -17,36 +17,39 @@ class RecvTimeout(TestCase):
 
     def test_recv_timeout_vs_keepalive(self) -> None:
         """verify that receive timeout as used via ping() is different to keep alive timeout"""
-        host = "127.0.0.1"
-
-        recv_timeout = 4
-        keep_alive = recv_timeout * 2
-        mqtt_client = MQTT.MQTT(
-            broker=host,
-            socket_pool=socket,
-            connect_retries=1,
-            socket_timeout=recv_timeout // 2,
-            recv_timeout=recv_timeout,
-            keep_alive=keep_alive,
-        )
-
-        # Create a mock socket that will accept anything and return nothing.
-        socket_mock = Mock()
-        socket_mock.recv_into = Mock(side_effect=lambda ret_buf, buf_size: 0)
-        # pylint: disable=protected-access
-        mqtt_client._sock = socket_mock
-
-        mqtt_client._connected = lambda: True
-        start = time.monotonic()
-        with self.assertRaises(MQTT.MMQTTException):
-            mqtt_client.ping()
-
-        # Verify the mock interactions.
-        socket_mock.send.assert_called_once()
-        socket_mock.recv_into.assert_called()
-
-        now = time.monotonic()
-        assert recv_timeout <= (now - start) < keep_alive
+
+        for side_effect in [lambda ret_buf, buf_size: 0, socket.timeout]:
+            with self.subTest():
+                host = "127.0.0.1"
+
+                recv_timeout = 4
+                keep_alive = recv_timeout * 2
+                mqtt_client = MQTT.MQTT(
+                    broker=host,
+                    socket_pool=socket,
+                    connect_retries=1,
+                    socket_timeout=recv_timeout // 2,
+                    recv_timeout=recv_timeout,
+                    keep_alive=keep_alive,
+                )
+
+                # Create a mock socket that will accept anything and return nothing.
+                socket_mock = Mock()
+                socket_mock.recv_into = Mock(side_effect=side_effect)
+                # pylint: disable=protected-access
+                mqtt_client._sock = socket_mock
+
+                mqtt_client._connected = lambda: True
+                start = time.monotonic()
+                with self.assertRaises(MQTT.MMQTTException):
+                    mqtt_client.ping()
+
+                # Verify the mock interactions.
+                socket_mock.send.assert_called_once()
+                socket_mock.recv_into.assert_called()
+
+                now = time.monotonic()
+                assert recv_timeout <= (now - start) < keep_alive
 
 
 if __name__ == "__main__":