gh-130474: Create and implement flaky resource

Lib/test/libregrtest/cmdline.py

@@ -122,6 +122,8 @@
 
     tzdata -         Run tests that require timezone data.
 
+    flaky -          Run tests that are known to be unreliable/unstable.
+
 To enable all resources except one, use '-uall,-<resource>'.  For
 example, to run all the tests except for the gui tests, give the
 option '-uall,-gui'.

Lib/test/libregrtest/utils.py

@@ -33,7 +33,7 @@
 
 
 ALL_RESOURCES = ('audio', 'curses', 'largefile', 'network',
-                 'decimal', 'cpu', 'subprocess', 'urlfetch', 'gui', 'walltime')
+                 'decimal', 'cpu', 'subprocess', 'urlfetch', 'gui', 'walltime', 'flaky')
 
 # Other resources excluded from --use=all:
 #

Lib/test/test_glob.py

@@ -7,7 +7,7 @@
 import warnings
 
 from test import support
-from test.support import is_wasi, Py_DEBUG
+from test.support import is_wasi, Py_DEBUG, requires_resource
 from test.support.os_helper import (TESTFN, skip_unless_symlink,
                                     can_symlink, create_empty_file, change_cwd)
 
@@ -521,7 +521,7 @@ class SymlinkLoopGlobTests(unittest.TestCase):
     # gh-109959: On Linux, glob._isdir() and glob._lexists() can return False
     # randomly when checking the "link/" symbolic link.
     # https://github.com/python/cpython/issues/109959#issuecomment-2577550700
-    @unittest.skip("flaky test")
+    @requires_resource('flaky')
     def test_selflink(self):
         tempdir = TESTFN + "_dir"
         os.makedirs(tempdir)

Misc/NEWS.d/next/Tests/2025-02-23-21-20-52.gh-issue-130474.dEckCL.rst

@@ -0,0 +1,2 @@
+Add the ``flaky`` resource for flagging tests with unreliable outcomes
+using the :py:deco:`!test.support.required_resource` decorator.