transport nullmodem (#1591)

pymodbus/transport/nullmodem.py

@@ -0,0 +1,115 @@
+"""Null modem transport.
+
+This is a special transport, mostly thought of for testing.
+
+NullModem interconnect 2 transport objects and transfers calls:
+    - server.listen()
+        - dummy
+    - client.connect()
+        - call client.connection_made()
+        - call server.connection_made()
+    - client/server.close()
+        - call client.connection_lost()
+        - call server.connection_lost()
+    - server/client.send
+        - call client/server.data_received()
+
+"""
+from __future__ import annotations
+
+import asyncio
+
+from pymodbus.logging import Log
+from pymodbus.transport.transport import Transport
+
+
+class DummyTransport(asyncio.BaseTransport):
+    """Use in connection_made calls."""
+
+    def close(self):
+        """Define dummy."""
+
+    def get_protocol(self):
+        """Define dummy."""
+
+    def is_closing(self):
+        """Define dummy."""
+
+    def set_protocol(self, _protocol):
+        """Define dummy."""
+
+    def abort(self):
+        """Define dummy."""
+
+
+class NullModem(Transport):
+    """Transport layer.
+
+    Contains methods to act as a null modem between 2 objects.
+    (Allowing tests to be shortcut without actual network calls)
+    """
+
+    nullmodem_client: NullModem = None
+    nullmodem_server: NullModem = None
+
+    def __init__(self, *arg):
+        """Overwrite init."""
+        self.is_server: bool = False
+        self.other_end: NullModem = None
+        super().__init__(*arg)
+
+    async def transport_connect(self) -> bool:
+        """Handle generic connect and call on to specific transport connect."""
+        Log.debug("NullModem: Simulate connect on {}", self.comm_params.comm_name)
+        if not self.loop:
+            self.loop = asyncio.get_running_loop()
+        if self.nullmodem_server:
+            self.__class__.nullmodem_client = self
+            self.other_end = self.nullmodem_server
+            self.nullmodem_server.other_end = self
+            self.cb_connection_made()
+            self.other_end.cb_connection_made()
+            return True
+        return False
+
+    async def transport_listen(self):
+        """Handle generic listen and call on to specific transport listen."""
+        Log.debug("NullModem: Simulate listen on {}", self.comm_params.comm_name)
+        if not self.loop:
+            self.loop = asyncio.get_running_loop()
+        self.is_server = True
+        self.__class__.nullmodem_server = self
+        return DummyTransport()
+
+    # -------------------------------- #
+    # Helper methods for child classes #
+    # -------------------------------- #
+    async def send(self, data: bytes) -> bool:
+        """Send request.
+
+        :param data: non-empty bytes object with data to send.
+        """
+        Log.debug("NullModem: simulate send {}", data, ":hex")
+        self.other_end.data_received(data)
+        return True
+
+    def close(self, reconnect: bool = False) -> None:
+        """Close connection.
+
+        :param reconnect: (default false), try to reconnect
+        """
+        self.recv_buffer = b""
+        if not reconnect:
+            if self.nullmodem_client:
+                self.nullmodem_client.cb_connection_lost(None)
+            if self.nullmodem_server:
+                self.nullmodem_server.cb_connection_lost(None)
+            self.__class__.nullmodem_client = None
+            self.__class__.nullmodem_server = None
+
+    # ----------------- #
+    # The magic methods #
+    # ----------------- #
+    def __str__(self) -> str:
+        """Build a string representation of the connection."""
+        return f"{self.__class__.__name__}({self.comm_params.comm_name})"

pymodbus/transport/transport.py

@@ -1,4 +1,4 @@
-"""Base for all transport types."""
+"""Transport layer."""
 # mypy: disable-error-code="name-defined"
 # needed because asyncio.Server is not defined (to mypy) in v3.8.16
 from __future__ import annotations
@@ -94,7 +94,6 @@ def __init__(
 
         self.reconnect_delay_current: float = 0.0
         self.transport: asyncio.BaseTransport | asyncio.Server = None
-        self.protocol: asyncio.BaseProtocol = None
         self.loop: asyncio.AbstractEventLoop = None
         self.reconnect_task: asyncio.Task = None
         self.recv_buffer: bytes = b""
@@ -266,9 +265,9 @@ async def transport_connect(self) -> bool:
         Log.debug("Connecting {}", self.comm_params.comm_name)
         if not self.loop:
             self.loop = asyncio.get_running_loop()
-        self.transport, self.protocol = None, None
+        self.transport = None
         try:
-            self.transport, self.protocol = await asyncio.wait_for(
+            self.transport, _protocol = await asyncio.wait_for(
                 self.call_connect_listen(),
                 timeout=self.comm_params.timeout_connect,
             )
@@ -346,9 +345,9 @@ def error_received(self, exc):
         Log.debug("-> error_received {}", exc)
         raise RuntimeError(str(exc))
 
-    # -------------------------------- #
-    # Helper methods for child classes #
-    # -------------------------------- #
+    # ----------------------------------- #
+    # Helper methods for external classes #
+    # ----------------------------------- #
     async def send(self, data: bytes) -> bool:
         """Send request.
 
@@ -369,7 +368,6 @@ def close(self, reconnect: bool = False) -> None:
                 self.transport.abort()
             self.transport.close()
             self.transport = None
-        self.protocol = None
         if not reconnect and self.reconnect_task:
             self.reconnect_task.cancel()
             self.reconnect_task = None

test/sub_transport/conftest.py

@@ -10,6 +10,7 @@
 import pytest
 import pytest_asyncio
 
+from pymodbus.transport.nullmodem import NullModem
 from pymodbus.transport.transport import Transport
 
 
@@ -38,21 +39,6 @@ def prepare_baseparams(use_port):
     return BaseParams
 
 
-class DummySocket:  # pylint: disable=too-few-public-methods
-    """Socket simulator for test."""
-
-    def __init__(self):
-        """Initialize."""
-        self.close = mock.Mock()
-        self.abort = mock.Mock()
-
-
-@pytest.fixture(name="dummy_socket")
-def prepare_dummysocket():
-    """Prepare dummy_socket class."""
-    return DummySocket
-
-
 @pytest.fixture(name="commparams")
 def prepare_testparams():
     """Prepare CommParamsClass object."""
@@ -82,6 +68,44 @@ async def prepare_transport():
     return transport
 
 
+@pytest.fixture(name="nullmodem")
+async def prepare_nullmodem():
+    """Prepare nullmodem object."""
+    transport = NullModem(
+        BaseParams.comm_name,
+        BaseParams.reconnect_delay,
+        BaseParams.reconnect_delay_max,
+        BaseParams.timeout_connect,
+        mock.Mock(name="cb_connection_made"),
+        mock.Mock(name="cb_connection_lost"),
+        mock.Mock(name="cb_handle_data", return_value=0),
+    )
+    transport.__class__.nullmodem_client = None
+    transport.__class__.nullmodem_server = None
+    with suppress(RuntimeError):
+        transport.loop = asyncio.get_running_loop()
+    return transport
+
+
+@pytest.fixture(name="nullmodem_server")
+async def prepare_nullmodem_server():
+    """Prepare nullmodem object."""
+    transport = NullModem(
+        BaseParams.comm_name,
+        BaseParams.reconnect_delay,
+        BaseParams.reconnect_delay_max,
+        BaseParams.timeout_connect,
+        mock.Mock(name="cb_connection_made"),
+        mock.Mock(name="cb_connection_lost"),
+        mock.Mock(name="cb_handle_data", return_value=0),
+    )
+    transport.__class__.nullmodem_client = None
+    transport.__class__.nullmodem_server = None
+    with suppress(RuntimeError):
+        transport.loop = asyncio.get_running_loop()
+    return transport
+
+
 @pytest_asyncio.fixture(name="transport_server")
 async def prepare_transport_server():
     """Prepare transport object."""

test/sub_transport/test_basic.py

@@ -5,6 +5,8 @@
 import pytest
 from serial import SerialException
 
+from pymodbus.transport.nullmodem import DummyTransport
+
 
 class TestBasicTransport:
     """Test transport module, base part."""
@@ -45,10 +47,10 @@ async def test_str_magic(self, params, transport):
         """Test magic."""
         assert str(transport) == f"Transport({params.comm_name})"
 
-    async def test_connection_made(self, dummy_socket, transport, commparams):
+    async def test_connection_made(self, transport, commparams):
         """Test connection_made()."""
         transport.loop = None
-        transport.connection_made(dummy_socket())
+        transport.connection_made(DummyTransport())
         assert transport.transport
         assert not transport.recv_buffer
         assert not transport.reconnect_task
@@ -76,9 +78,11 @@ async def test_connection_lost(self, transport):
         transport.close()
         assert not transport.reconnect_task
 
-    async def test_close(self, dummy_socket, transport):
+    async def test_close(self, transport):
         """Test close()."""
-        socket = dummy_socket()
+        socket = DummyTransport()
+        socket.abort = mock.Mock()
+        socket.close = mock.Mock()
         transport.connection_made(socket)
         transport.cb_connection_made.reset_mock()
         transport.cb_connection_lost.reset_mock()

test/sub_transport/test_nullmodem.py

@@ -0,0 +1,118 @@
+"""Test transport."""
+
+from pymodbus.transport.nullmodem import DummyTransport
+
+
+class TestNullModemTransport:
+    """Test null modem module."""
+
+    async def test_str_magic(self, nullmodem, params):
+        """Test magic."""
+        str(nullmodem)
+        assert str(nullmodem) == f"NullModem({params.comm_name})"
+
+    def test_DummyTransport(self):
+        """Test DummyTransport class."""
+        socket = DummyTransport()
+        socket.close()
+        socket.get_protocol()
+        socket.is_closing()
+        socket.set_protocol(None)
+        socket.abort()
+
+    def test_class_variables(self, nullmodem, nullmodem_server):
+        """Test connection_made()."""
+        assert not nullmodem.nullmodem_client
+        assert not nullmodem.nullmodem_server
+        assert not nullmodem_server.nullmodem_client
+        assert not nullmodem_server.nullmodem_server
+        nullmodem.__class__.nullmodem_client = self
+        nullmodem.is_server = False
+        nullmodem_server.__class__.nullmodem_server = self
+        nullmodem_server.is_server = True
+
+        assert nullmodem.nullmodem_client == nullmodem_server.nullmodem_client
+        assert nullmodem.nullmodem_server == nullmodem_server.nullmodem_server
+
+    async def test_transport_connect(self, nullmodem):
+        """Test connection_made()."""
+        nullmodem.loop = None
+        assert not await nullmodem.transport_connect()
+        assert not nullmodem.nullmodem_server
+        assert not nullmodem.nullmodem_client
+        assert nullmodem.loop
+        nullmodem.cb_connection_made.assert_not_called()
+        nullmodem.cb_connection_lost.assert_not_called()
+        nullmodem.cb_handle_data.assert_not_called()
+
+    async def test_transport_listen(self, nullmodem_server):
+        """Test connection_made()."""
+        nullmodem_server.loop = None
+        assert await nullmodem_server.transport_listen()
+        assert nullmodem_server.is_server
+        assert nullmodem_server.nullmodem_server
+        assert not nullmodem_server.nullmodem_client
+        assert nullmodem_server.loop
+        nullmodem_server.cb_connection_made.assert_not_called()
+        nullmodem_server.cb_connection_lost.assert_not_called()
+        nullmodem_server.cb_handle_data.assert_not_called()
+
+    async def test_connected(self, nullmodem, nullmodem_server):
+        """Test connection is correct."""
+        assert await nullmodem_server.transport_listen()
+        assert await nullmodem.transport_connect()
+        assert nullmodem.nullmodem_client
+        assert nullmodem.nullmodem_server
+        assert nullmodem.loop
+        assert not nullmodem.is_server
+        assert nullmodem_server.is_server
+        nullmodem.cb_connection_made.assert_called_once()
+        nullmodem.cb_connection_lost.assert_not_called()
+        nullmodem.cb_handle_data.assert_not_called()
+        nullmodem_server.cb_connection_made.assert_called_once()
+        nullmodem_server.cb_connection_lost.assert_not_called()
+        nullmodem_server.cb_handle_data.assert_not_called()
+
+    async def test_client_close(self, nullmodem, nullmodem_server):
+        """Test close()."""
+        assert await nullmodem_server.transport_listen()
+        assert await nullmodem.transport_connect()
+        nullmodem.close()
+        assert not nullmodem.nullmodem_client
+        assert not nullmodem.nullmodem_server
+        nullmodem.cb_connection_made.assert_called_once()
+        nullmodem.cb_connection_lost.assert_called_once()
+        nullmodem.cb_handle_data.assert_not_called()
+        nullmodem_server.cb_connection_made.assert_called_once()
+        nullmodem_server.cb_connection_lost.assert_called_once()
+        nullmodem_server.cb_handle_data.assert_not_called()
+
+    async def test_server_close(self, nullmodem, nullmodem_server):
+        """Test close()."""
+        assert await nullmodem_server.transport_listen()
+        assert await nullmodem.transport_connect()
+        nullmodem_server.close()
+        assert not nullmodem.nullmodem_client
+        assert not nullmodem.nullmodem_server
+        nullmodem.cb_connection_made.assert_called_once()
+        nullmodem.cb_connection_lost.assert_called_once()
+        nullmodem.cb_handle_data.assert_not_called()
+        nullmodem_server.cb_connection_made.assert_called_once()
+        nullmodem_server.cb_connection_lost.assert_called_once()
+        nullmodem_server.cb_handle_data.assert_not_called()
+
+    async def test_data(self, nullmodem, nullmodem_server):
+        """Test data exchange."""
+        data = b"abcd"
+        assert await nullmodem_server.transport_listen()
+        assert await nullmodem.transport_connect()
+        assert await nullmodem.send(data)
+        assert nullmodem_server.recv_buffer == data
+        assert not nullmodem.recv_buffer
+        nullmodem.cb_handle_data.assert_not_called()
+        nullmodem_server.cb_handle_data.assert_called_once()
+        assert await nullmodem_server.send(data)
+        assert nullmodem_server.recv_buffer == data
+        assert nullmodem.recv_buffer == data
+        nullmodem.cb_handle_data.assert_called_once()
+        nullmodem_server.cb_handle_data.assert_called_once()