FS_NONASCII moves to test.support.os_helper in Python 3.10, so add a compatibility shim to support both sides.

Author: jaraco

tests/fixtures.py

@@ -5,7 +5,8 @@
 import shutil
 import tempfile
 import textwrap
-import test.support
+
+from .py39compat import FS_NONASCII
 
 from importlib_metadata._compat import pathlib, contextlib
 
@@ -218,7 +219,7 @@ def build_files(file_defs, prefix=pathlib.Path()):
 
 class FileBuilder:
     def unicode_filename(self):
-        return test.support.FS_NONASCII or \
+        return FS_NONASCII or \
             self.skip("File system does not support non-ascii.")
 
 

tests/py39compat.py

@@ -0,0 +1,4 @@
+try:
+    from test.support.os_helpers import FS_NONASCII
+except ImportError:
+    from test.support import FS_NONASCII  # noqa