use pymodbus simulator instead of Python mock

clickplc/tests/simulator_setup.json

@@ -0,0 +1,66 @@
+{
+    "server_list": {
+        "server": {
+            "comm": "tcp",
+            "host": "0.0.0.0",
+            "port": 5020,
+            "ignore_missing_slaves": false,
+            "framer": "socket",
+            "identity": {
+                "VendorName": "pymodbus",
+                "ProductCode": "PM",
+                "VendorUrl": "https://github.com/pymodbus-dev/pymodbus/",
+                "ProductName": "pymodbus Server",
+                "ModelName": "pymodbus Server",
+                "MajorMinorRevision": "3.1.0"
+            }
+        }
+    },
+    "device_list": {
+        "device": {
+            "setup": {
+                "co size": 65536,
+                "di size": 65536,
+                "hr size": 65536,
+                "ir size": 65536,
+                "shared blocks": false,
+                "type exception": false,
+                "defaults": {
+                    "value": {
+                        "bits": 0,
+                        "uint16": 0,
+                        "uint32": 0,
+                        "float32": 0.0,
+                        "string": " "
+                    },
+                    "action": {
+                        "bits": null,
+                        "uint16": null,
+                        "uint32": null,
+                        "float32": null,
+                        "string": null
+                    }
+                }
+            },
+            "invalid": [],
+            "write": [
+                [0, 65535],
+                [131073, 262143]
+            ],
+            "bits": [
+                [0, 65535]
+            ],
+            "uint16": [
+                [131073, 262143]
+            ],
+            "uint32": [
+            ],
+            "float32": [
+            ],
+            "string": [
+            ],
+            "repeat": [
+            ]
+        }
+    }
+}

clickplc/tests/test_driver.py

@@ -1,14 +1,31 @@
 """Test the driver correctly parses a tags file and responds with correct data."""
-from unittest import mock
+import contextlib
+import os
 
 import pytest
+from pymodbus.server import ModbusSimulatorServer
 
-from clickplc import command_line
-from clickplc.mock import ClickPLC
+from clickplc import ClickPLC, command_line
 
-ADDRESS = 'fakeip'
-# from clickplc.driver import ClickPLC
+# Test against pymodbus simulator
+ADDRESS = '127.0.0.1'
+autouse = True
+## Uncomment below to use a real PLC
 # ADDRESS = '172.16.0.168'
+# autouse = False
+
+@pytest.fixture(scope='session', autouse=autouse)
+async def _sim():
+    """Start a modbus server simulator."""
+    serverTask = ModbusSimulatorServer(
+        modbus_server = 'server',
+        modbus_device = 'device',
+        json_file = os.path.join('clickplc', 'tests', 'simulator_setup.json')
+    )
+    await serverTask.run_forever(only_start=True)
+    yield
+    with contextlib.suppress(NameError):
+        await serverTask.stop()
 
 
 @pytest.fixture(scope='session')
@@ -42,7 +59,6 @@ def expected_tags():
     }
 
 
-@mock.patch('clickplc.ClickPLC', ClickPLC)
 def test_driver_cli(capsys):
     """Confirm the commandline interface works without a tags file."""
     command_line([ADDRESS])
@@ -52,7 +68,6 @@ def test_driver_cli(capsys):
     assert 'df100' in captured.out
 
 
-@mock.patch('clickplc.ClickPLC', ClickPLC)
 def test_driver_cli_tags(capsys):
     """Confirm the commandline interface works with a tags file."""
     command_line([ADDRESS, 'clickplc/tests/plc_tags.csv'])

clickplc/util.py

@@ -26,10 +26,11 @@ class AsyncioModbusClient:
     def __init__(self, address, timeout=1):
         """Set up communication parameters."""
         self.ip = address
+        port = 5020 if address == '127.0.0.1' else 502  # pymodbus simulator is 127.0.0.1:5020
         self.timeout = timeout
         self._detect_pymodbus_version()
         if self.pymodbus30plus:
-            self.client = AsyncModbusTcpClient(address, timeout=timeout)
+            self.client = AsyncModbusTcpClient(address, timeout=timeout, port=port)
         else:  # 2.x
             self.client = ReconnectingAsyncioModbusTcpClient()
         self.lock = asyncio.Lock()

setup.py

@@ -27,6 +27,7 @@
     ],
     extras_require={
         'test': [
+            'pymodbus[simulator]>=3.0.2',
             'pytest',
             'pytest-asyncio>=0.23.7,<=0.23.9',
             'pytest-cov',