fix: ruff findings

tests/test_init_system.py

@@ -9,12 +9,9 @@ Covers:
 
 Spec: ADR 0008, §8.4, §8.5, §8.6, §8.7, §8.8
 """
-import os
 import sqlite3
-import tempfile
-from datetime import datetime, timedelta, timezone
 from pathlib import Path
-from unittest.mock import patch, MagicMock, PropertyMock
+from unittest.mock import patch, MagicMock
 
 import pytest
 
@@ -24,7 +21,6 @@ sys.path.insert(0, str(Path(__file__).parent.parent / "src"))
 from fenris.init_system import (
     InitSystem,
     detect_init_system,
-    get_init_system,
     reset_init_system_cache,
     _systemd_enable,
     _systemd_disable,
@@ -41,8 +37,6 @@ from fenris.init_system import (
     collect_now,
     query_service_state,
     journal_hint,
-    FENRIS_SV_DIR,
-    FENRIS_SERVICE_LINK,
     COLLECT_TIMEOUT_S,
 )
 from fenris.store import init_store