fix(socket-signal): add read timeout for SocketSignal ABC, and add notify_bec attribute

tests/test_socket.py

@@ -1,9 +1,51 @@
 import socket
+import time
 from unittest import mock
 
 import pytest
+from bec_server.device_server.tests.utils import DMMock
 
-from ophyd_devices.utils.socket import SocketIO
+from ophyd_devices.tests.utils import SocketMock
+from ophyd_devices.utils.controller import Controller
+from ophyd_devices.utils.socket import SocketIO, SocketSignal
+
+
+class DummySocketSignal(SocketSignal):
+    """Dummy SocketSignal class for testing the SocketSignal interface."""
+
+    def __init__(
+        self, name, controller: Controller, notify_bec=True, readback_timeout=None, **kwargs
+    ):
+        super().__init__(
+            name=name, notify_bec=notify_bec, readback_timeout=readback_timeout, **kwargs
+        )
+        self.controller = controller
+
+    def _socket_get(self) -> str:
+        self._metadata["timestamp"] = time.monotonic()
+        return self.controller.socket_put_and_receive("get")
+
+    def _socket_set(self, value: str):
+        self.controller.socket_put_and_receive(value)
+
+
+@pytest.fixture
+def controller():
+    dm = DMMock()
+    controller = Controller(
+        name="controller",
+        socket_cls=SocketMock,
+        socket_host="localhost",
+        socket_port=8080,
+        device_manager=dm,
+    )
+    controller.on()
+    return controller
+
+
+@pytest.fixture
+def signal(controller):
+    return DummySocketSignal(name="signal", controller=controller, readback_timeout=0.1)
 
 
 class DummySocket:
@@ -85,3 +127,63 @@ def test_close():
     socketio.close()
     assert socketio.sock == None
     assert socketio.is_open == False
+
+
+def test_socket_signal_get(signal):
+    """
+    Test that the get method of the SocketSignal class correctly retrives values from the socket,
+    and that it implements the caching and timeout mechanism to avoid excessive socket reads and/or recursions.
+    """
+    # First get should call the socket and cache the value
+    controller = signal.controller
+
+    controller.sock: SocketMock
+    controller.sock.buffer_recv = [b"value2", b"value1"]
+    signal._readback_timeout = 0
+    readback = signal.read()
+    assert readback[signal.name]["value"] == "value2"
+    readback2 = signal.read()
+    assert readback2[signal.name]["value"] == "value1"
+    assert readback[signal.name]["timestamp"] != readback2[signal.name]["timestamp"]
+    controller.sock.buffer_recv = [b"value2"]
+
+    cb_bucket = []
+    read_value = None
+    signal._readback_timeout = 10
+
+    def _test_cb(value, old_value, **kwargs):
+        cb_bucket.append((value, old_value))
+        read_value = signal.read()
+
+    signal.subscribe(_test_cb, event_type=signal.SUB_VALUE, run=False)
+    signal._readback_timeout = 10
+    signal._last_readback = 0  # reset the last readback time to force a socket read
+    readback1 = signal.read()
+    assert readback1[signal.name]["value"] == "value2"
+    # The value should be cached, so it should not change
+    assert cb_bucket == [("value2", "value1")]
+    readback2 = signal.read()
+    for entry in ("value", "timestamp"):
+        assert readback1[signal.name][entry] == readback2[signal.name][entry]
+
+
+def test_socket_signal_put(signal):
+    """
+    Test that the put method of the SocketSignal class correctly sends values to the socket,
+    and that it implements the necessary subscription notifications for value changes.
+    """
+    controller = signal.controller
+    controller.sock: SocketMock
+    cb_bucket = []
+    initial_value = signal._readback
+
+    def _test_cb(value, old_value, **kwargs):
+        cb_bucket.append((value, old_value))
+
+    signal.subscribe(_test_cb, event_type=signal.SUB_SETPOINT, run=False)
+    signal.put("new_value")
+    assert controller.sock.buffer_put == [b"new_value\n"]
+    assert cb_bucket == [("new_value", initial_value)]
+    signal.put("another_value")
+    assert controller.sock.buffer_put == [b"new_value\n", b"another_value\n"]
+    assert cb_bucket == [("new_value", initial_value), ("another_value", "new_value")]