Address pylint issues

(cherry picked from commit 3c6124a093)

bin/tests/system/isctest/kasp.py

@@ -315,6 +315,7 @@ def check_dnssecstatus(server, zone, keys, policy=None, view=None):
         assert f"key: {key.tag}" in response
 
 
+# pylint: disable=too-many-branches,too-many-locals
 def _check_signatures(signatures, covers, fqdn, keys):
     now = KeyTimingMetadata.now()
     numsigs = 0

bin/tests/system/ksr/tests_ksr.py

@@ -18,8 +18,6 @@ import shutil
 import time
 from typing import List, Optional
 
-from datetime import datetime
-
 import isctest
 from isctest.kasp import (
     Key,
@@ -40,7 +38,7 @@ def check_file_contents_equal(file1, file2):
         return " ".join(line.split())
 
     def read_lines(file_path):
-        with open(file_path, "r") as file:
+        with open(file_path, "r", encoding="utf-8") as file:
             return [normalize_line(line) for line in file.readlines()]
 
     lines1 = read_lines(file1)