Return timestamp from file in UTC, since borg expects UTC (#62)

return timestamp from file in UTC, since borg expects UTC timestamps

src/borg_import/helpers/testsuite/test_timestamps.py

@@ -1,5 +1,5 @@
 import os
-from datetime import datetime
+from datetime import datetime, timezone
 from pathlib import Path
 
 import pytest
@@ -11,7 +11,7 @@ def test_datetime_from_mtime(tmpdir):
     fn = Path(str(tmpdir.join("mtime_test")))
     with fn.open("w"):
         pass
-    dt = datetime(1999, 12, 31, 23, 59, 59)
+    dt = datetime(1999, 12, 31, 23, 59, 59, tzinfo=timezone.utc)
     atime = mtime = dt.timestamp()
     os.utime(str(fn), (atime, mtime))  # touch file
     assert datetime_from_mtime(fn) == dt

src/borg_import/helpers/timestamps.py

@@ -1,4 +1,4 @@
-from datetime import datetime
+from datetime import datetime, timezone
 
 
 def datetime_from_mtime(path):
@@ -10,7 +10,7 @@ def datetime_from_mtime(path):
     at backup time).
     """
     t = path.stat().st_mtime
-    return datetime.fromtimestamp(t)
+    return datetime.fromtimestamp(t, tz=timezone.utc)
 
 
 def datetime_from_string(s):