gh-76785: Fixes for test.support.interpreters (gh-112982)

This involves a number of changes for PEP 734.

1 files changed, 0 insertions, 1136 deletions

diff --git a/Lib/test/test_interpreters.py b/Lib/test/test_interpreters.py
deleted file mode 100644
index 5663706..0000000
--- a/Lib/test/test_interpreters.py
+++ /dev/null
@@ -1,1136 +0,0 @@
-import contextlib
-import json
-import os
-import os.path
-import sys
-import threading
-from textwrap import dedent
-import unittest
-import time
-
-from test import support
-from test.support import import_helper
-from test.support import threading_helper
-from test.support import os_helper
-_interpreters = import_helper.import_module('_xxsubinterpreters')
-_channels = import_helper.import_module('_xxinterpchannels')
-from test.support import interpreters
-
-
-def _captured_script(script):
-    r, w = os.pipe()
-    indented = script.replace('\n', '\n                ')
-    wrapped = dedent(f"""
-        import contextlib
-        with open({w}, 'w', encoding='utf-8') as spipe:
-            with contextlib.redirect_stdout(spipe):
-                {indented}
-        """)
-    return wrapped, open(r, encoding='utf-8')
-
-
-def clean_up_interpreters():
-    for interp in interpreters.list_all():
-        if interp.id == 0:  # main
-            continue
-        try:
-            interp.close()
-        except RuntimeError:
-            pass  # already destroyed
-
-
-def _run_output(interp, request, channels=None):
-    script, rpipe = _captured_script(request)
-    with rpipe:
-        interp.run(script, channels=channels)
-        return rpipe.read()
-
-
-@contextlib.contextmanager
-def _running(interp):
-    r, w = os.pipe()
-    def run():
-        interp.run(dedent(f"""
-            # wait for "signal"
-            with open({r}) as rpipe:
-                rpipe.read()
-            """))
-
-    t = threading.Thread(target=run)
-    t.start()
-
-    yield
-
-    with open(w, 'w') as spipe:
-        spipe.write('done')
-    t.join()
-
-
-class TestBase(unittest.TestCase):
-
-    def pipe(self):
-        def ensure_closed(fd):
-            try:
-                os.close(fd)
-            except OSError:
-                pass
-        r, w = os.pipe()
-        self.addCleanup(lambda: ensure_closed(r))
-        self.addCleanup(lambda: ensure_closed(w))
-        return r, w
-
-    def tearDown(self):
-        clean_up_interpreters()
-
-
-class CreateTests(TestBase):
-
-    def test_in_main(self):
-        interp = interpreters.create()
-        self.assertIsInstance(interp, interpreters.Interpreter)
-        self.assertIn(interp, interpreters.list_all())
-
-    def test_in_thread(self):
-        lock = threading.Lock()
-        interp = None
-        def f():
-            nonlocal interp
-            interp = interpreters.create()
-            lock.acquire()
-            lock.release()
-        t = threading.Thread(target=f)
-        with lock:
-            t.start()
-        t.join()
-        self.assertIn(interp, interpreters.list_all())
-
-    def test_in_subinterpreter(self):
-        main, = interpreters.list_all()
-        interp = interpreters.create()
-        out = _run_output(interp, dedent("""
-            from test.support import interpreters
-            interp = interpreters.create()
-            print(interp.id)
-            """))
-        interp2 = interpreters.Interpreter(int(out))
-        self.assertEqual(interpreters.list_all(), [main, interp, interp2])
-
-    def test_after_destroy_all(self):
-        before = set(interpreters.list_all())
-        # Create 3 subinterpreters.
-        interp_lst = []
-        for _ in range(3):
-            interps = interpreters.create()
-            interp_lst.append(interps)
-        # Now destroy them.
-        for interp in interp_lst:
-            interp.close()
-        # Finally, create another.
-        interp = interpreters.create()
-        self.assertEqual(set(interpreters.list_all()), before | {interp})
-
-    def test_after_destroy_some(self):
-        before = set(interpreters.list_all())
-        # Create 3 subinterpreters.
-        interp1 = interpreters.create()
-        interp2 = interpreters.create()
-        interp3 = interpreters.create()
-        # Now destroy 2 of them.
-        interp1.close()
-        interp2.close()
-        # Finally, create another.
-        interp = interpreters.create()
-        self.assertEqual(set(interpreters.list_all()), before | {interp3, interp})
-
-
-class GetCurrentTests(TestBase):
-
-    def test_main(self):
-        main = interpreters.get_main()
-        current = interpreters.get_current()
-        self.assertEqual(current, main)
-
-    def test_subinterpreter(self):
-        main = _interpreters.get_main()
-        interp = interpreters.create()
-        out = _run_output(interp, dedent("""
-            from test.support import interpreters
-            cur = interpreters.get_current()
-            print(cur.id)
-            """))
-        current = interpreters.Interpreter(int(out))
-        self.assertNotEqual(current, main)
-
-
-class ListAllTests(TestBase):
-
-    def test_initial(self):
-        interps = interpreters.list_all()
-        self.assertEqual(1, len(interps))
-
-    def test_after_creating(self):
-        main = interpreters.get_current()
-        first = interpreters.create()
-        second = interpreters.create()
-
-        ids = []
-        for interp in interpreters.list_all():
-            ids.append(interp.id)
-
-        self.assertEqual(ids, [main.id, first.id, second.id])
-
-    def test_after_destroying(self):
-        main = interpreters.get_current()
-        first = interpreters.create()
-        second = interpreters.create()
-        first.close()
-
-        ids = []
-        for interp in interpreters.list_all():
-            ids.append(interp.id)
-
-        self.assertEqual(ids, [main.id, second.id])
-
-
-class TestInterpreterAttrs(TestBase):
-
-    def test_id_type(self):
-        main = interpreters.get_main()
-        current = interpreters.get_current()
-        interp = interpreters.create()
-        self.assertIsInstance(main.id, _interpreters.InterpreterID)
-        self.assertIsInstance(current.id, _interpreters.InterpreterID)
-        self.assertIsInstance(interp.id, _interpreters.InterpreterID)
-
-    def test_main_id(self):
-        main = interpreters.get_main()
-        self.assertEqual(main.id, 0)
-
-    def test_custom_id(self):
-        interp = interpreters.Interpreter(1)
-        self.assertEqual(interp.id, 1)
-
-        with self.assertRaises(TypeError):
-            interpreters.Interpreter('1')
-
-    def test_id_readonly(self):
-        interp = interpreters.Interpreter(1)
-        with self.assertRaises(AttributeError):
-            interp.id = 2
-
-    @unittest.skip('not ready yet (see bpo-32604)')
-    def test_main_isolated(self):
-        main = interpreters.get_main()
-        self.assertFalse(main.isolated)
-
-    @unittest.skip('not ready yet (see bpo-32604)')
-    def test_subinterpreter_isolated_default(self):
-        interp = interpreters.create()
-        self.assertFalse(interp.isolated)
-
-    def test_subinterpreter_isolated_explicit(self):
-        interp1 = interpreters.create(isolated=True)
-        interp2 = interpreters.create(isolated=False)
-        self.assertTrue(interp1.isolated)
-        self.assertFalse(interp2.isolated)
-
-    @unittest.skip('not ready yet (see bpo-32604)')
-    def test_custom_isolated_default(self):
-        interp = interpreters.Interpreter(1)
-        self.assertFalse(interp.isolated)
-
-    def test_custom_isolated_explicit(self):
-        interp1 = interpreters.Interpreter(1, isolated=True)
-        interp2 = interpreters.Interpreter(1, isolated=False)
-        self.assertTrue(interp1.isolated)
-        self.assertFalse(interp2.isolated)
-
-    def test_isolated_readonly(self):
-        interp = interpreters.Interpreter(1)
-        with self.assertRaises(AttributeError):
-            interp.isolated = True
-
-    def test_equality(self):
-        interp1 = interpreters.create()
-        interp2 = interpreters.create()
-        self.assertEqual(interp1, interp1)
-        self.assertNotEqual(interp1, interp2)
-
-
-class TestInterpreterIsRunning(TestBase):
-
-    def test_main(self):
-        main = interpreters.get_main()
-        self.assertTrue(main.is_running())
-
-    @unittest.skip('Fails on FreeBSD')
-    def test_subinterpreter(self):
-        interp = interpreters.create()
-        self.assertFalse(interp.is_running())
-
-        with _running(interp):
-            self.assertTrue(interp.is_running())
-        self.assertFalse(interp.is_running())
-
-    def test_finished(self):
-        r, w = self.pipe()
-        interp = interpreters.create()
-        interp.run(f"""if True:
-            import os
-            os.write({w}, b'x')
-            """)
-        self.assertFalse(interp.is_running())
-        self.assertEqual(os.read(r, 1), b'x')
-
-    def test_from_subinterpreter(self):
-        interp = interpreters.create()
-        out = _run_output(interp, dedent(f"""
-            import _xxsubinterpreters as _interpreters
-            if _interpreters.is_running({interp.id}):
-                print(True)
-            else:
-                print(False)
-            """))
-        self.assertEqual(out.strip(), 'True')
-
-    def test_already_destroyed(self):
-        interp = interpreters.create()
-        interp.close()
-        with self.assertRaises(RuntimeError):
-            interp.is_running()
-
-    def test_does_not_exist(self):
-        interp = interpreters.Interpreter(1_000_000)
-        with self.assertRaises(RuntimeError):
-            interp.is_running()
-
-    def test_bad_id(self):
-        interp = interpreters.Interpreter(-1)
-        with self.assertRaises(ValueError):
-            interp.is_running()
-
-    def test_with_only_background_threads(self):
-        r_interp, w_interp = self.pipe()
-        r_thread, w_thread = self.pipe()
-
-        DONE = b'D'
-        FINISHED = b'F'
-
-        interp = interpreters.create()
-        interp.run(f"""if True:
-            import os
-            import threading
-
-            def task():
-                v = os.read({r_thread}, 1)
-                assert v == {DONE!r}
-                os.write({w_interp}, {FINISHED!r})
-            t = threading.Thread(target=task)
-            t.start()
-            """)
-        self.assertFalse(interp.is_running())
-
-        os.write(w_thread, DONE)
-        interp.run('t.join()')
-        self.assertEqual(os.read(r_interp, 1), FINISHED)
-
-
-class TestInterpreterClose(TestBase):
-
-    def test_basic(self):
-        main = interpreters.get_main()
-        interp1 = interpreters.create()
-        interp2 = interpreters.create()
-        interp3 = interpreters.create()
-        self.assertEqual(set(interpreters.list_all()),
-                         {main, interp1, interp2, interp3})
-        interp2.close()
-        self.assertEqual(set(interpreters.list_all()),
-                         {main, interp1, interp3})
-
-    def test_all(self):
-        before = set(interpreters.list_all())
-        interps = set()
-        for _ in range(3):
-            interp = interpreters.create()
-            interps.add(interp)
-        self.assertEqual(set(interpreters.list_all()), before | interps)
-        for interp in interps:
-            interp.close()
-        self.assertEqual(set(interpreters.list_all()), before)
-
-    def test_main(self):
-        main, = interpreters.list_all()
-        with self.assertRaises(RuntimeError):
-            main.close()
-
-        def f():
-            with self.assertRaises(RuntimeError):
-                main.close()
-
-        t = threading.Thread(target=f)
-        t.start()
-        t.join()
-
-    def test_already_destroyed(self):
-        interp = interpreters.create()
-        interp.close()
-        with self.assertRaises(RuntimeError):
-            interp.close()
-
-    def test_does_not_exist(self):
-        interp = interpreters.Interpreter(1_000_000)
-        with self.assertRaises(RuntimeError):
-            interp.close()
-
-    def test_bad_id(self):
-        interp = interpreters.Interpreter(-1)
-        with self.assertRaises(ValueError):
-            interp.close()
-
-    def test_from_current(self):
-        main, = interpreters.list_all()
-        interp = interpreters.create()
-        out = _run_output(interp, dedent(f"""
-            from test.support import interpreters
-            interp = interpreters.Interpreter({int(interp.id)})
-            try:
-                interp.close()
-            except RuntimeError:
-                print('failed')
-            """))
-        self.assertEqual(out.strip(), 'failed')
-        self.assertEqual(set(interpreters.list_all()), {main, interp})
-
-    def test_from_sibling(self):
-        main, = interpreters.list_all()
-        interp1 = interpreters.create()
-        interp2 = interpreters.create()
-        self.assertEqual(set(interpreters.list_all()),
-                         {main, interp1, interp2})
-        interp1.run(dedent(f"""
-            from test.support import interpreters
-            interp2 = interpreters.Interpreter(int({interp2.id}))
-            interp2.close()
-            interp3 = interpreters.create()
-            interp3.close()
-            """))
-        self.assertEqual(set(interpreters.list_all()), {main, interp1})
-
-    def test_from_other_thread(self):
-        interp = interpreters.create()
-        def f():
-            interp.close()
-
-        t = threading.Thread(target=f)
-        t.start()
-        t.join()
-
-    @unittest.skip('Fails on FreeBSD')
-    def test_still_running(self):
-        main, = interpreters.list_all()
-        interp = interpreters.create()
-        with _running(interp):
-            with self.assertRaises(RuntimeError):
-                interp.close()
-            self.assertTrue(interp.is_running())
-
-    def test_subthreads_still_running(self):
-        r_interp, w_interp = self.pipe()
-        r_thread, w_thread = self.pipe()
-
-        FINISHED = b'F'
-
-        interp = interpreters.create()
-        interp.run(f"""if True:
-            import os
-            import threading
-            import time
-
-            done = False
-
-            def notify_fini():
-                global done
-                done = True
-                t.join()
-            threading._register_atexit(notify_fini)
-
-            def task():
-                while not done:
-                    time.sleep(0.1)
-                os.write({w_interp}, {FINISHED!r})
-            t = threading.Thread(target=task)
-            t.start()
-            """)
-        interp.close()
-
-        self.assertEqual(os.read(r_interp, 1), FINISHED)
-
-
-class TestInterpreterRun(TestBase):
-
-    def test_success(self):
-        interp = interpreters.create()
-        script, file = _captured_script('print("it worked!", end="")')
-        with file:
-            interp.run(script)
-            out = file.read()
-
-        self.assertEqual(out, 'it worked!')
-
-    def test_failure(self):
-        interp = interpreters.create()
-        with self.assertRaises(interpreters.RunFailedError):
-            interp.run('raise Exception')
-
-    def test_in_thread(self):
-        interp = interpreters.create()
-        script, file = _captured_script('print("it worked!", end="")')
-        with file:
-            def f():
-                interp.run(script)
-
-            t = threading.Thread(target=f)
-            t.start()
-            t.join()
-            out = file.read()
-
-        self.assertEqual(out, 'it worked!')
-
-    @support.requires_fork()
-    def test_fork(self):
-        interp = interpreters.create()
-        import tempfile
-        with tempfile.NamedTemporaryFile('w+', encoding='utf-8') as file:
-            file.write('')
-            file.flush()
-
-            expected = 'spam spam spam spam spam'
-            script = dedent(f"""
-                import os
-                try:
-                    os.fork()
-                except RuntimeError:
-                    with open('{file.name}', 'w', encoding='utf-8') as out:
-                        out.write('{expected}')
-                """)
-            interp.run(script)
-
-            file.seek(0)
-            content = file.read()
-            self.assertEqual(content, expected)
-
-    @unittest.skip('Fails on FreeBSD')
-    def test_already_running(self):
-        interp = interpreters.create()
-        with _running(interp):
-            with self.assertRaises(RuntimeError):
-                interp.run('print("spam")')
-
-    def test_does_not_exist(self):
-        interp = interpreters.Interpreter(1_000_000)
-        with self.assertRaises(RuntimeError):
-            interp.run('print("spam")')
-
-    def test_bad_id(self):
-        interp = interpreters.Interpreter(-1)
-        with self.assertRaises(ValueError):
-            interp.run('print("spam")')
-
-    def test_bad_script(self):
-        interp = interpreters.create()
-        with self.assertRaises(TypeError):
-            interp.run(10)
-
-    def test_bytes_for_script(self):
-        interp = interpreters.create()
-        with self.assertRaises(TypeError):
-            interp.run(b'print("spam")')
-
-    def test_with_background_threads_still_running(self):
-        r_interp, w_interp = self.pipe()
-        r_thread, w_thread = self.pipe()
-
-        RAN = b'R'
-        DONE = b'D'
-        FINISHED = b'F'
-
-        interp = interpreters.create()
-        interp.run(f"""if True:
-            import os
-            import threading
-
-            def task():
-                v = os.read({r_thread}, 1)
-                assert v == {DONE!r}
-                os.write({w_interp}, {FINISHED!r})
-            t = threading.Thread(target=task)
-            t.start()
-            os.write({w_interp}, {RAN!r})
-            """)
-        interp.run(f"""if True:
-            os.write({w_interp}, {RAN!r})
-            """)
-
-        os.write(w_thread, DONE)
-        interp.run('t.join()')
-        self.assertEqual(os.read(r_interp, 1), RAN)
-        self.assertEqual(os.read(r_interp, 1), RAN)
-        self.assertEqual(os.read(r_interp, 1), FINISHED)
-
-    # test_xxsubinterpreters covers the remaining Interpreter.run() behavior.
-
-
-class StressTests(TestBase):
-
-    # In these tests we generally want a lot of interpreters,
-    # but not so many that any test takes too long.
-
-    @support.requires_resource('cpu')
-    def test_create_many_sequential(self):
-        alive = []
-        for _ in range(100):
-            interp = interpreters.create()
-            alive.append(interp)
-
-    @support.requires_resource('cpu')
-    def test_create_many_threaded(self):
-        alive = []
-        def task():
-            interp = interpreters.create()
-            alive.append(interp)
-        threads = (threading.Thread(target=task) for _ in range(200))
-        with threading_helper.start_threads(threads):
-            pass
-
-
-class StartupTests(TestBase):
-
-    # We want to ensure the initial state of subinterpreters
-    # matches expectations.
-
-    _subtest_count = 0
-
-    @contextlib.contextmanager
-    def subTest(self, *args):
-        with super().subTest(*args) as ctx:
-            self._subtest_count += 1
-            try:
-                yield ctx
-            finally:
-                if self._debugged_in_subtest:
-                    if self._subtest_count == 1:
-                        # The first subtest adds a leading newline, so we
-                        # compensate here by not printing a trailing newline.
-                        print('### end subtest debug ###', end='')
-                    else:
-                        print('### end subtest debug ###')
-                self._debugged_in_subtest = False
-
-    def debug(self, msg, *, header=None):
-        if header:
-            self._debug(f'--- {header} ---')
-            if msg:
-                if msg.endswith(os.linesep):
-                    self._debug(msg[:-len(os.linesep)])
-                else:
-                    self._debug(msg)
-                    self._debug('<no newline>')
-            self._debug('------')
-        else:
-            self._debug(msg)
-
-    _debugged = False
-    _debugged_in_subtest = False
-    def _debug(self, msg):
-        if not self._debugged:
-            print()
-            self._debugged = True
-        if self._subtest is not None:
-            if True:
-                if not self._debugged_in_subtest:
-                    self._debugged_in_subtest = True
-                    print('### start subtest debug ###')
-                print(msg)
-        else:
-            print(msg)
-
-    def create_temp_dir(self):
-        import tempfile
-        tmp = tempfile.mkdtemp(prefix='test_interpreters_')
-        tmp = os.path.realpath(tmp)
-        self.addCleanup(os_helper.rmtree, tmp)
-        return tmp
-
-    def write_script(self, *path, text):
-        filename = os.path.join(*path)
-        dirname = os.path.dirname(filename)
-        if dirname:
-            os.makedirs(dirname, exist_ok=True)
-        with open(filename, 'w', encoding='utf-8') as outfile:
-            outfile.write(dedent(text))
-        return filename
-
-    @support.requires_subprocess()
-    def run_python(self, argv, *, cwd=None):
-        # This method is inspired by
-        # EmbeddingTestsMixin.run_embedded_interpreter() in test_embed.py.
-        import shlex
-        import subprocess
-        if isinstance(argv, str):
-            argv = shlex.split(argv)
-        argv = [sys.executable, *argv]
-        try:
-            proc = subprocess.run(
-                argv,
-                cwd=cwd,
-                capture_output=True,
-                text=True,
-            )
-        except Exception as exc:
-            self.debug(f'# cmd: {shlex.join(argv)}')
-            if isinstance(exc, FileNotFoundError) and not exc.filename:
-                if os.path.exists(argv[0]):
-                    exists = 'exists'
-                else:
-                    exists = 'does not exist'
-                self.debug(f'{argv[0]} {exists}')
-            raise  # re-raise
-        assert proc.stderr == '' or proc.returncode != 0, proc.stderr
-        if proc.returncode != 0 and support.verbose:
-            self.debug(f'# python3 {shlex.join(argv[1:])} failed:')
-            self.debug(proc.stdout, header='stdout')
-            self.debug(proc.stderr, header='stderr')
-        self.assertEqual(proc.returncode, 0)
-        self.assertEqual(proc.stderr, '')
-        return proc.stdout
-
-    def test_sys_path_0(self):
-        # The main interpreter's sys.path[0] should be used by subinterpreters.
-        script = '''
-            import sys
-            from test.support import interpreters
-
-            orig = sys.path[0]
-
-            interp = interpreters.create()
-            interp.run(f"""if True:
-                import json
-                import sys
-                print(json.dumps({{
-                    'main': {orig!r},
-                    'sub': sys.path[0],
-                }}, indent=4), flush=True)
-                """)
-            '''
-        # <tmp>/
-        #   pkg/
-        #     __init__.py
-        #     __main__.py
-        #     script.py
-        #   script.py
-        cwd = self.create_temp_dir()
-        self.write_script(cwd, 'pkg', '__init__.py', text='')
-        self.write_script(cwd, 'pkg', '__main__.py', text=script)
-        self.write_script(cwd, 'pkg', 'script.py', text=script)
-        self.write_script(cwd, 'script.py', text=script)
-
-        cases = [
-            ('script.py', cwd),
-            ('-m script', cwd),
-            ('-m pkg', cwd),
-            ('-m pkg.script', cwd),
-            ('-c "import script"', ''),
-        ]
-        for argv, expected in cases:
-            with self.subTest(f'python3 {argv}'):
-                out = self.run_python(argv, cwd=cwd)
-                data = json.loads(out)
-                sp0_main, sp0_sub = data['main'], data['sub']
-                self.assertEqual(sp0_sub, sp0_main)
-                self.assertEqual(sp0_sub, expected)
-        # XXX Also check them all with the -P cmdline flag?
-
-
-class FinalizationTests(TestBase):
-
-    def test_gh_109793(self):
-        import subprocess
-        argv = [sys.executable, '-c', '''if True:
-            import _xxsubinterpreters as _interpreters
-            interpid = _interpreters.create()
-            raise Exception
-            ''']
-        proc = subprocess.run(argv, capture_output=True, text=True)
-        self.assertIn('Traceback', proc.stderr)
-        if proc.returncode == 0 and support.verbose:
-            print()
-            print("--- cmd unexpected succeeded ---")
-            print(f"stdout:\n{proc.stdout}")
-            print(f"stderr:\n{proc.stderr}")
-            print("------")
-        self.assertEqual(proc.returncode, 1)
-
-
-class TestIsShareable(TestBase):
-
-    def test_default_shareables(self):
-        shareables = [
-                # singletons
-                None,
-                # builtin objects
-                b'spam',
-                'spam',
-                10,
-                -10,
-                True,
-                False,
-                100.0,
-                (),
-                (1, ('spam', 'eggs'), True),
-                ]
-        for obj in shareables:
-            with self.subTest(obj):
-                shareable = interpreters.is_shareable(obj)
-                self.assertTrue(shareable)
-
-    def test_not_shareable(self):
-        class Cheese:
-            def __init__(self, name):
-                self.name = name
-            def __str__(self):
-                return self.name
-
-        class SubBytes(bytes):
-            """A subclass of a shareable type."""
-
-        not_shareables = [
-                # singletons
-                NotImplemented,
-                ...,
-                # builtin types and objects
-                type,
-                object,
-                object(),
-                Exception(),
-                # user-defined types and objects
-                Cheese,
-                Cheese('Wensleydale'),
-                SubBytes(b'spam'),
-                ]
-        for obj in not_shareables:
-            with self.subTest(repr(obj)):
-                self.assertFalse(
-                    interpreters.is_shareable(obj))
-
-
-class TestChannels(TestBase):
-
-    def test_create(self):
-        r, s = interpreters.create_channel()
-        self.assertIsInstance(r, interpreters.RecvChannel)
-        self.assertIsInstance(s, interpreters.SendChannel)
-
-    def test_list_all(self):
-        self.assertEqual(interpreters.list_all_channels(), [])
-        created = set()
-        for _ in range(3):
-            ch = interpreters.create_channel()
-            created.add(ch)
-        after = set(interpreters.list_all_channels())
-        self.assertEqual(after, created)
-
-    def test_shareable(self):
-        rch, sch = interpreters.create_channel()
-
-        self.assertTrue(
-            interpreters.is_shareable(rch))
-        self.assertTrue(
-            interpreters.is_shareable(sch))
-
-        sch.send_nowait(rch)
-        sch.send_nowait(sch)
-        rch2 = rch.recv()
-        sch2 = rch.recv()
-
-        self.assertEqual(rch2, rch)
-        self.assertEqual(sch2, sch)
-
-    def test_is_closed(self):
-        rch, sch = interpreters.create_channel()
-        rbefore = rch.is_closed
-        sbefore = sch.is_closed
-        rch.close()
-        rafter = rch.is_closed
-        safter = sch.is_closed
-
-        self.assertFalse(rbefore)
-        self.assertFalse(sbefore)
-        self.assertTrue(rafter)
-        self.assertTrue(safter)
-
-
-class TestRecvChannelAttrs(TestBase):
-
-    def test_id_type(self):
-        rch, _ = interpreters.create_channel()
-        self.assertIsInstance(rch.id, _channels.ChannelID)
-
-    def test_custom_id(self):
-        rch = interpreters.RecvChannel(1)
-        self.assertEqual(rch.id, 1)
-
-        with self.assertRaises(TypeError):
-            interpreters.RecvChannel('1')
-
-    def test_id_readonly(self):
-        rch = interpreters.RecvChannel(1)
-        with self.assertRaises(AttributeError):
-            rch.id = 2
-
-    def test_equality(self):
-        ch1, _ = interpreters.create_channel()
-        ch2, _ = interpreters.create_channel()
-        self.assertEqual(ch1, ch1)
-        self.assertNotEqual(ch1, ch2)
-
-
-class TestSendChannelAttrs(TestBase):
-
-    def test_id_type(self):
-        _, sch = interpreters.create_channel()
-        self.assertIsInstance(sch.id, _channels.ChannelID)
-
-    def test_custom_id(self):
-        sch = interpreters.SendChannel(1)
-        self.assertEqual(sch.id, 1)
-
-        with self.assertRaises(TypeError):
-            interpreters.SendChannel('1')
-
-    def test_id_readonly(self):
-        sch = interpreters.SendChannel(1)
-        with self.assertRaises(AttributeError):
-            sch.id = 2
-
-    def test_equality(self):
-        _, ch1 = interpreters.create_channel()
-        _, ch2 = interpreters.create_channel()
-        self.assertEqual(ch1, ch1)
-        self.assertNotEqual(ch1, ch2)
-
-
-class TestSendRecv(TestBase):
-
-    def test_send_recv_main(self):
-        r, s = interpreters.create_channel()
-        orig = b'spam'
-        s.send_nowait(orig)
-        obj = r.recv()
-
-        self.assertEqual(obj, orig)
-        self.assertIsNot(obj, orig)
-
-    def test_send_recv_same_interpreter(self):
-        interp = interpreters.create()
-        interp.run(dedent("""
-            from test.support import interpreters
-            r, s = interpreters.create_channel()
-            orig = b'spam'
-            s.send_nowait(orig)
-            obj = r.recv()
-            assert obj == orig, 'expected: obj == orig'
-            assert obj is not orig, 'expected: obj is not orig'
-            """))
-
-    @unittest.skip('broken (see BPO-...)')
-    def test_send_recv_different_interpreters(self):
-        r1, s1 = interpreters.create_channel()
-        r2, s2 = interpreters.create_channel()
-        orig1 = b'spam'
-        s1.send_nowait(orig1)
-        out = _run_output(
-            interpreters.create(),
-            dedent(f"""
-                obj1 = r.recv()
-                assert obj1 == b'spam', 'expected: obj1 == orig1'
-                # When going to another interpreter we get a copy.
-                assert id(obj1) != {id(orig1)}, 'expected: obj1 is not orig1'
-                orig2 = b'eggs'
-                print(id(orig2))
-                s.send_nowait(orig2)
-                """),
-            channels=dict(r=r1, s=s2),
-            )
-        obj2 = r2.recv()
-
-        self.assertEqual(obj2, b'eggs')
-        self.assertNotEqual(id(obj2), int(out))
-
-    def test_send_recv_different_threads(self):
-        r, s = interpreters.create_channel()
-
-        def f():
-            while True:
-                try:
-                    obj = r.recv()
-                    break
-                except interpreters.ChannelEmptyError:
-                    time.sleep(0.1)
-            s.send(obj)
-        t = threading.Thread(target=f)
-        t.start()
-
-        orig = b'spam'
-        s.send(orig)
-        obj = r.recv()
-        t.join()
-
-        self.assertEqual(obj, orig)
-        self.assertIsNot(obj, orig)
-
-    def test_send_recv_nowait_main(self):
-        r, s = interpreters.create_channel()
-        orig = b'spam'
-        s.send_nowait(orig)
-        obj = r.recv_nowait()
-
-        self.assertEqual(obj, orig)
-        self.assertIsNot(obj, orig)
-
-    def test_send_recv_nowait_main_with_default(self):
-        r, _ = interpreters.create_channel()
-        obj = r.recv_nowait(None)
-
-        self.assertIsNone(obj)
-
-    def test_send_recv_nowait_same_interpreter(self):
-        interp = interpreters.create()
-        interp.run(dedent("""
-            from test.support import interpreters
-            r, s = interpreters.create_channel()
-            orig = b'spam'
-            s.send_nowait(orig)
-            obj = r.recv_nowait()
-            assert obj == orig, 'expected: obj == orig'
-            # When going back to the same interpreter we get the same object.
-            assert obj is not orig, 'expected: obj is not orig'
-            """))
-
-    @unittest.skip('broken (see BPO-...)')
-    def test_send_recv_nowait_different_interpreters(self):
-        r1, s1 = interpreters.create_channel()
-        r2, s2 = interpreters.create_channel()
-        orig1 = b'spam'
-        s1.send_nowait(orig1)
-        out = _run_output(
-            interpreters.create(),
-            dedent(f"""
-                obj1 = r.recv_nowait()
-                assert obj1 == b'spam', 'expected: obj1 == orig1'
-                # When going to another interpreter we get a copy.
-                assert id(obj1) != {id(orig1)}, 'expected: obj1 is not orig1'
-                orig2 = b'eggs'
-                print(id(orig2))
-                s.send_nowait(orig2)
-                """),
-            channels=dict(r=r1, s=s2),
-            )
-        obj2 = r2.recv_nowait()
-
-        self.assertEqual(obj2, b'eggs')
-        self.assertNotEqual(id(obj2), int(out))
-
-    def test_recv_timeout(self):
-        r, _ = interpreters.create_channel()
-        with self.assertRaises(TimeoutError):
-            r.recv(timeout=1)
-
-    def test_recv_channel_does_not_exist(self):
-        ch = interpreters.RecvChannel(1_000_000)
-        with self.assertRaises(interpreters.ChannelNotFoundError):
-            ch.recv()
-
-    def test_send_channel_does_not_exist(self):
-        ch = interpreters.SendChannel(1_000_000)
-        with self.assertRaises(interpreters.ChannelNotFoundError):
-            ch.send(b'spam')
-
-    def test_recv_nowait_channel_does_not_exist(self):
-        ch = interpreters.RecvChannel(1_000_000)
-        with self.assertRaises(interpreters.ChannelNotFoundError):
-            ch.recv_nowait()
-
-    def test_send_nowait_channel_does_not_exist(self):
-        ch = interpreters.SendChannel(1_000_000)
-        with self.assertRaises(interpreters.ChannelNotFoundError):
-            ch.send_nowait(b'spam')
-
-    def test_recv_nowait_empty(self):
-        ch, _ = interpreters.create_channel()
-        with self.assertRaises(interpreters.ChannelEmptyError):
-            ch.recv_nowait()
-
-    def test_recv_nowait_default(self):
-        default = object()
-        rch, sch = interpreters.create_channel()
-        obj1 = rch.recv_nowait(default)
-        sch.send_nowait(None)
-        sch.send_nowait(1)
-        sch.send_nowait(b'spam')
-        sch.send_nowait(b'eggs')
-        obj2 = rch.recv_nowait(default)
-        obj3 = rch.recv_nowait(default)
-        obj4 = rch.recv_nowait()
-        obj5 = rch.recv_nowait(default)
-        obj6 = rch.recv_nowait(default)
-
-        self.assertIs(obj1, default)
-        self.assertIs(obj2, None)
-        self.assertEqual(obj3, 1)
-        self.assertEqual(obj4, b'spam')
-        self.assertEqual(obj5, b'eggs')
-        self.assertIs(obj6, default)
-
-    def test_send_buffer(self):
-        buf = bytearray(b'spamspamspam')
-        obj = None
-        rch, sch = interpreters.create_channel()
-
-        def f():
-            nonlocal obj
-            while True:
-                try:
-                    obj = rch.recv()
-                    break
-                except interpreters.ChannelEmptyError:
-                    time.sleep(0.1)
-        t = threading.Thread(target=f)
-        t.start()
-
-        sch.send_buffer(buf)
-        t.join()
-
-        self.assertIsNot(obj, buf)
-        self.assertIsInstance(obj, memoryview)
-        self.assertEqual(obj, buf)
-
-        buf[4:8] = b'eggs'
-        self.assertEqual(obj, buf)
-        obj[4:8] = b'ham.'
-        self.assertEqual(obj, buf)
-
-    def test_send_buffer_nowait(self):
-        buf = bytearray(b'spamspamspam')
-        rch, sch = interpreters.create_channel()
-        sch.send_buffer_nowait(buf)
-        obj = rch.recv()
-
-        self.assertIsNot(obj, buf)
-        self.assertIsInstance(obj, memoryview)
-        self.assertEqual(obj, buf)
-
-        buf[4:8] = b'eggs'
-        self.assertEqual(obj, buf)
-        obj[4:8] = b'ham.'
-        self.assertEqual(obj, buf)