Bug report

I found at least three cases where _testinternalcapi is just imported, we cannot do that, because other python implementation which reuse our test cases will fail on this.

1. cpython/Lib/test/test_cmd_line.py

   Lines 785 to 826 in 34ddcc3

   	def check_pythonmalloc(self, env_var, name):
   	code = 'import _testinternalcapi; print(_testinternalcapi.pymem_getallocatorsname())'
   	env = dict(os.environ)
   	env.pop('PYTHONDEVMODE', None)
   	if env_var is not None:
   	env['PYTHONMALLOC'] = env_var
   	else:
   	env.pop('PYTHONMALLOC', None)
   	args = (sys.executable, '-c', code)
   	proc = subprocess.run(args,
   	stdout=subprocess.PIPE,
   	stderr=subprocess.STDOUT,
   	universal_newlines=True,
   	env=env)
   	self.assertEqual(proc.stdout.rstrip(), name)
   	self.assertEqual(proc.returncode, 0)
   	def test_pythonmalloc(self):
   	# Test the PYTHONMALLOC environment variable
   	pymalloc = support.with_pymalloc()
   	if pymalloc:
   	default_name = 'pymalloc_debug' if support.Py_DEBUG else 'pymalloc'
   	default_name_debug = 'pymalloc_debug'
   	else:
   	default_name = 'malloc_debug' if support.Py_DEBUG else 'malloc'
   	default_name_debug = 'malloc_debug'
   	tests = [
   	(None, default_name),
   	('debug', default_name_debug),
   	('malloc', 'malloc'),
   	('malloc_debug', 'malloc_debug'),
   	]
   	if pymalloc:
   	tests.extend((
   	('pymalloc', 'pymalloc'),
   	('pymalloc_debug', 'pymalloc_debug'),
   	))
   	for env_var, name in tests:
   	with self.subTest(env_var=env_var, name=name):
   	self.check_pythonmalloc(env_var, name)

2. cpython/Lib/test/test_import/__init__.py

   Line 25 in 34ddcc3

   import _testinternalcapi

3. cpython/Lib/test/test_opcache.py

   Line 8 in 34ddcc3

   import _testinternalcapi

There can be several options to solve this:

1. Use import _testinternalcapi with except ImportError, when some places might need it
2. Use import_helper.import_module to skip some tests where this module is required
3. Use @cpython_only decorator

Linked PRs

• gh-109721: Guard _testinternalcapi imports in tests #109722