chore: add send_reply tests (#230)

tests/test_send_reply.py

@@ -0,0 +1,53 @@
+import os
+import traceback
+from types import TracebackType
+from typing import Any, Callable, Dict, List, Optional, Type, Union
+from unittest.mock import Mock
+
+import pytest
+
+from dbus_fast.constants import ErrorType, MessageType
+from dbus_fast.errors import DBusError
+from dbus_fast.message import Message
+from dbus_fast.message_bus import BaseMessageBus, SendReply
+
+
+@pytest.fixture(autouse=True)
+def mock_address() -> None:
+    original_address = os.environ.get("DBUS_SESSION_BUS_ADDRESS")
+    os.environ["DBUS_SESSION_BUS_ADDRESS"] = "unix:path=/dev/null"
+    yield
+    if original_address is None:
+        del os.environ["DBUS_SESSION_BUS_ADDRESS"]
+    else:
+        os.environ["DBUS_SESSION_BUS_ADDRESS"] = original_address
+
+
+def test_send_reply_exception() -> None:
+    """Test that SendReply sends an error message when DBusError is raised."""
+
+    messages = []
+
+    class MockBus(BaseMessageBus):
+        def send(self, msg: Message) -> None:
+            messages.append(msg)
+
+        def send_message(self, msg: Message) -> None:
+            messages.append(msg)
+
+        def _setup_socket(self) -> None:
+            pass
+
+    mock_message_bus = MockBus()
+    mock_message = Message(
+        path="/test/path", interface="test.interface", member="test_member", serial=1
+    )
+    send_reply = SendReply(mock_message_bus, mock_message)
+
+    with send_reply as reply:
+        raise DBusError(ErrorType.DISCONNECTED, "Disconnected", None)
+
+    assert len(messages) == 1
+    assert messages[0].message_type == MessageType.ERROR
+    assert messages[0].error_name == "org.freedesktop.DBus.Error.Disconnected"
+    assert messages[0].reply_serial == 1