diff --git a/paas_app_charmer/_gunicorn/logrotate.py b/paas_app_charmer/_gunicorn/logrotate.py
index b009137..548b315 100644
--- a/paas_app_charmer/_gunicorn/logrotate.py
+++ b/paas_app_charmer/_gunicorn/logrotate.py
@@ -7,10 +7,13 @@
 
 It will be injected into the container and does not depend on non-standard libraries.
 """
+
 import argparse
 import datetime
 import glob
 import os
+
+# this script runs similarly to a shell script, disable the warning for using subprocess
 import subprocess  # nosec B404
 import time
 
diff --git a/tests/unit/flask/test_charm.py b/tests/unit/flask/test_charm.py
index 4970d9e..a6234a2 100644
--- a/tests/unit/flask/test_charm.py
+++ b/tests/unit/flask/test_charm.py
@@ -97,9 +97,24 @@ def test_log_rotate(tmp_path):
     files = list(tmp_path.iterdir())
     assert len(files) == 1
     archive = files[0]
+    # if the filename doesn't match the pattern, a ValueError will be raised here
     datetime.datetime.strptime(archive.name, "access-%Y-%m-%d-%H-%M-%S.log")
 
 
+def test_log_rotate_not_rotated(tmp_path):
+    """
+    arrange: create a small log file
+    act: run the log rotate function
+    assert: the log file should not be rotated
+    """
+    log_file = tmp_path / "access.log"
+    log_file.touch()
+    assert not logrotate.rotate(str(log_file.absolute()))
+    assert log_file.exists()
+    files = list(tmp_path.iterdir())
+    assert len(files) == 1
+
+
 def test_log_rotate_cleanup(tmp_path):
     """
     arrange: create a log file larger than the max log file size, along with many archive files