fix timezone handling and logging fallback robustness

tests/test_reports.py

@@ -5,10 +5,12 @@ Tests inventory reports, completeness reports, duplicate reports, and summary re
 
 import csv
 import json
+import os
+import time
 import pytest
 from io import StringIO
 from pathlib import Path
-from datetime import datetime
+from datetime import datetime, timezone
 from vlm.models import SeasonCompleteness, DuplicateGroup, VideoFile, MovieIdentity, SeriesIdentity
 from vlm.reports import (
     generate_inventory_report,
@@ -205,12 +207,13 @@ class TestInventoryReport:
     
     def test_timestamp_formatting(self):
         """Test that timestamps are formatted as ISO 8601."""
+        naive_local = datetime(2023, 6, 15, 14, 30, 45)
         files = [
             VideoFile(
                 Path("/test.mkv"),
                 "test.mkv",
                 1000,
-                datetime(2023, 6, 15, 14, 30, 45),
+                naive_local,
                 "movie"
             )
         ]
@@ -219,7 +222,38 @@ class TestInventoryReport:
         report = generate_inventory_report(files, "csv", library_root)
         
         # Check timestamp format
-        assert "2023-06-15T14:30:45" in report
+        expected_utc = naive_local.astimezone(timezone.utc).strftime("%Y-%m-%dT%H:%M:%S")
+        assert expected_utc in report
+
+    @pytest.mark.skipif(not hasattr(time, "tzset"), reason="tzset not available on this platform")
+    def test_naive_timestamp_is_converted_from_local_to_utc(self, monkeypatch):
+        """Test report conversion for naive timestamps uses local timezone semantics."""
+        original_tz = os.environ.get("TZ")
+        try:
+            monkeypatch.setenv("TZ", "Etc/GMT-2")
+            time.tzset()
+
+            naive_local = datetime(2023, 6, 15, 14, 30, 45)
+            expected_utc = naive_local.astimezone(timezone.utc).strftime("%Y-%m-%dT%H:%M:%S")
+
+            files = [
+                VideoFile(
+                    Path("/test.mkv"),
+                    "test.mkv",
+                    1000,
+                    naive_local,
+                    "movie"
+                )
+            ]
+            report = generate_inventory_report(files, "json", Path("/test"))
+            data = json.loads(report)
+            assert data["files"][0]["modified_timestamp"] == expected_utc
+        finally:
+            if original_tz is None:
+                monkeypatch.delenv("TZ", raising=False)
+            else:
+                monkeypatch.setenv("TZ", original_tz)
+            time.tzset()
 
 
 class TestCompletenessReport: