Fix ConfigManagingActor to handle relative paths (#1005)

The check that compared the event path with the config path was not
working as expected when the config path was a relative path.

Author: daniel-zullo-frequenz

RELEASE_NOTES.md

@@ -31,3 +31,4 @@
 - Fixed a bug where sending tasks in the data sourcing actor might have not been properly awaited.
 - Updated the logical meter documentation to reflect the latest changes.
 - Fixed a bug in the code examples in the getting-started tutorial.
+- Fixed a bug in `ConfigManagingActor` that was not properly comparing the event path to the config file path when the config file is a relative path.

src/frequenz/sdk/actor/_config_managing.py

@@ -93,7 +93,7 @@ async def _run(self) -> None:
         async for event in self._file_watcher:
             # Since we are watching the whole parent directory, we need to make sure
             # we only react to events related to the configuration file.
-            if event.path != self._config_path:
+            if not event.path.samefile(self._config_path):
                 continue
 
             match event.type:

tests/actor/test_config_manager.py

@@ -2,6 +2,7 @@
 # Copyright © 2022 Frequenz Energy-as-a-Service GmbH
 
 """Test for ConfigManager."""
+import os
 import pathlib
 from typing import Any
 
@@ -48,17 +49,6 @@ class TestActorConfigManager:
 
     @pytest.fixture()
     def config_file(self, tmp_path: pathlib.Path) -> pathlib.Path:
-        """Create a test config file."""
-        file_path = tmp_path / TestActorConfigManager.conf_path
-        file_path.parent.mkdir()
-        file_path.touch()
-        file_path.write_text(TestActorConfigManager.conf_content)
-        return file_path
-
-    @pytest.fixture()
-    def real_config_file(
-        self, tmp_path: pathlib.Path = pathlib.Path("/tmp/")
-    ) -> pathlib.Path:
         """Create a test config file."""
         file_path = tmp_path / TestActorConfigManager.conf_path
         if not file_path.exists():
@@ -98,3 +88,26 @@ async def test_update(self, config_file: pathlib.Path) -> None:
             assert config.get("var2") == str(number)
             assert config.get("var3") is None
             assert config_file.read_text() == create_content(number=number)
+
+    async def test_update_relative_path(self, config_file: pathlib.Path) -> None:
+        """Test ConfigManagingActor with a relative path."""
+        config_channel: Broadcast[dict[str, Any]] = Broadcast(
+            name="Config Channel", resend_latest=True
+        )
+        config_receiver = config_channel.new_receiver()
+
+        current_dir = pathlib.Path.cwd()
+        relative_path = os.path.relpath(config_file, current_dir)
+
+        async with ConfigManagingActor(relative_path, config_channel.new_sender()):
+            config = await config_receiver.receive()
+            assert config is not None
+            assert config.get("var2") is None
+
+            number = 8
+            config_file.write_text(create_content(number=number))
+
+            config = await config_receiver.receive()
+            assert config is not None
+            assert config.get("var2") == str(number)
+            assert config_file.read_text() == create_content(number=number)