adds tests for server to check if loading from file is working

tests/server/test_server.py

@@ -1,8 +1,15 @@
+import json
 import signal
-
-from pytest_mock import MockerFixture
+from pathlib import Path
+from typing import Any
 
 import pydase
+import pydase.components
+import pydase.units as u
+from pydase.data_service.state_manager import load_state
+from pydase.server.server import Server
+from pytest import LogCaptureFixture
+from pytest_mock import MockerFixture
 
 
 def test_signal_handling(mocker: MockerFixture):
@@ -33,3 +40,64 @@ def test_signal_handling(mocker: MockerFixture):
     # Simulate receiving a SIGINT signal for the second time
     server.handle_exit(signal.SIGINT, None)
     mock_exit.assert_called_once_with(1)
+
+
+class Service(pydase.DataService):
+    def __init__(self, **kwargs: Any) -> None:
+        super().__init__(**kwargs)
+        self.some_unit: u.Quantity = 1.2 * u.units.A
+        self.some_float = 1.0
+        self._property_attr = 1337.0
+
+    @property
+    def property_attr(self) -> float:
+        return self._property_attr
+
+    @property_attr.setter
+    @load_state
+    def property_attr(self, value: float) -> None:
+        self._property_attr = value
+
+
+CURRENT_STATE = Service().serialize()
+
+LOAD_STATE = {
+    "some_float": {
+        "type": "float",
+        "value": 10.0,
+        "readonly": False,
+        "doc": None,
+    },
+    "property_attr": {
+        "type": "float",
+        "value": 1337.1,
+        "readonly": False,
+        "doc": None,
+    },
+    "some_unit": {
+        "type": "Quantity",
+        "value": {"magnitude": 12.0, "unit": "A"},
+        "readonly": False,
+        "doc": None,
+    },
+}
+
+
+def test_load_state(tmp_path: Path, caplog: LogCaptureFixture) -> None:
+    # Create a StateManager instance with a temporary file
+    file = tmp_path / "test_state.json"
+
+    # Write a temporary JSON file to read back
+    with open(file, "w") as f:
+        json.dump(LOAD_STATE, f, indent=4)
+
+    service = Service()
+    Server(service, filename=str(file))
+
+    assert service.some_unit == u.Quantity(12, "A")
+    assert service.property_attr == 1337.1
+    assert service.some_float == 10.0
+
+    assert "'some_unit' changed to '12.0 A'" in caplog.text
+    assert "'some_float' changed to '10.0'" in caplog.text
+    assert "'property_attr' changed to '1337.1'" in caplog.text