tests: isolated: adjust expected file descriptors increase for python…

… 3.13

It looks like that with python 3.13, the increase in number of
opened file descriptors in `test_pipe_leakage` on Windows is
down from 6 to 3. Adjust the value for now, will investigate
later.

tests/unit/test_isolation.py

@@ -15,6 +15,7 @@
 import pytest
 
 from PyInstaller import isolated
+from PyInstaller import compat
 from PyInstaller.utils.tests import requires
 
 
@@ -179,7 +180,7 @@ def test_pipe_leakage():
  parent = Process()
 
  # Get this platform's *count open handles* method.
- open_fds = parent.num_handles if os.name == "nt" else parent.num_fds
+ open_fds = parent.num_handles if compat.is_win else parent.num_fds
  old = open_fds()
 
  # Creating an isolated.Python() does nothing.
@@ -193,8 +194,12 @@ def test_pipe_leakage():
  # opened when the sub-process is spawned. Then we close the two pipe end-points that were inherited by the child,
  # which closes two handles. Finally, we open file descriptors on the remaining two pipe end-point handles, and
  # perform os.fdopen() on those FDs to obtained buffered python "file" object. This adds two additional file
- # handles, bringing us to the total of six.
- EXPECTED_INCREASE_IN_FDS = (2 if os.name != "nt" else 6)
+ # handles, bringing us to the total of six. Starting with python 3.13, the increase seems to be down to three,
+ # instead.
+ if compat.is_win:
+ EXPECTED_INCREASE_IN_FDS = 3 if compat.is_py313 else 6
+ else:
+ EXPECTED_INCREASE_IN_FDS = 2
 
  with child:
  assert open_fds() == old + EXPECTED_INCREASE_IN_FDS