Tests fail on Windows due to PermissionError with NamedTemporaryFile

[denini08]

I was running the tests on my Windows machine and noticed a failure in test/test_utils.py caused by NamedTemporaryFile being opened twice, which is not allowed on Windows because the file is already open with an exclusive handle. It happend in the fixtures safe_tar_file and unsafe_tar_file.

Here’s the error I got:

E           PermissionError: [Errno 13] Permission denied: 
E           'C:\\Users\\user\\AppData\\Local\\Temp\\tmpeqruskgx'

C:\hostedtoolcache\windows\Python\3.12.8\x64\Lib\gzip.py:192: PermissionError

This issue happens when the tests try to open a NamedTemporaryFile path again using tarfile.open() while the temporary file is still open.

On Linux this works fine, but on Windows it fails due to file locking behavior.

I’ll try to open a PR with a fix that makes it compatible with both systems.