[QMI-0xx] Adding some discard_read tests.

qmi/core/transport.py

@@ -739,10 +739,7 @@ def discard_read(self) -> None:
         while True:
             try:
                 b, addr = self._safe_socket.recvfrom(4096)
-            except socket.timeout:
-                # no more bytes available
-                break
-            except BlockingIOError:
+            except (BlockingIOError, socket.timeout):
                 # no more bytes available
                 break
             except OSError:

tests/core/test_transport.py

@@ -587,6 +587,8 @@ async def the_call():
             if len(read) != 100:
                 raise AssertionError from ass
 
+            trans.discard_read()
+
         # Send some bytes from server to transport.
         loop = asyncio.get_event_loop()
         if loop.is_closed():
@@ -600,9 +602,11 @@ async def the_call():
 
         except qmi.core.exceptions.QMI_TimeoutException as tim:
             # Catch this as some servers apparently fragment the message to be max of 4096 bytes, so it does not crash
-            if len(trans._read_buffer) != 8092:
+            if len(trans._read_buffer) != 4096:
                 raise AssertionError from tim
 
+            trans.discard_read()
+
         if loop.is_running():
             loop.close()
 
@@ -710,6 +714,27 @@ def test_read_until_timeout(self):
         # Close transport.
         trans.close()
 
+    def test_discard_read(self):
+        """Test discarding read data."""
+        # Create UDP transport connected to local server.
+        trans = QMI_UdpTransport("localhost", self.server_port)
+        trans.open()
+
+        # Accept the connection on server side.
+        self.server_sock.connect((self.server_host, self.server_port + 1))
+        server_conn = self.server_sock
+        server_conn.settimeout(1.0)
+
+        # Send some bytes from server to transport.
+        testmsg = b"hello there"
+        server_conn.sendall(testmsg)
+
+        # Discard bytes through the transport.
+        trans.discard_read()
+        # Try to read, which should now except as the input buffer was discarded
+        with self.assertRaises(qmi.core.exceptions.QMI_TimeoutException):
+            trans.read(1, 0.0)
+
     def test_client_non_existing(self):
 
         # Try to create a server for non-existing client host name.