gh-121790: Fix interactive console initialization (#121793)

Co-authored-by: Łukasz Langa <lukasz@langa.pl>

Lib/test/test_repl.py

@@ -1,15 +1,27 @@
 """Test the interactive interpreter."""
 
 import os
+import select
 import subprocess
 import sys
 import unittest
 from textwrap import dedent
 from test import support
-from test.support import cpython_only, has_subprocess_support, SuppressCrashReport
-from test.support.script_helper import assert_python_failure, kill_python, assert_python_ok
+from test.support import (
+    cpython_only,
+    has_subprocess_support,
+    os_helper,
+    SuppressCrashReport,
+    SHORT_TIMEOUT,
+)
+from test.support.script_helper import kill_python
 from test.support.import_helper import import_module
 
+try:
+    import pty
+except ImportError:
+    pty = None
+
 
 if not has_subprocess_support:
     raise unittest.SkipTest("test module requires subprocess")
@@ -195,9 +207,56 @@ class TestInteractiveInterpreter(unittest.TestCase):
         expected = "(30, None, [\'def foo(x):\\n\', \'    return x + 1\\n\', \'\\n\'], \'<stdin>\')"
         self.assertIn(expected, output, expected)
 
-    def test_asyncio_repl_no_tty_fails(self):
-        assert assert_python_failure("-m", "asyncio")
+    def test_asyncio_repl_reaches_python_startup_script(self):
+        with os_helper.temp_dir() as tmpdir:
+            script = os.path.join(tmpdir, "pythonstartup.py")
+            with open(script, "w") as f:
+                f.write("print('pythonstartup done!')" + os.linesep)
+                f.write("exit(0)" + os.linesep)
 
+            env = os.environ.copy()
+            env["PYTHONSTARTUP"] = script
+            subprocess.check_call(
+                [sys.executable, "-m", "asyncio"],
+                stdout=subprocess.PIPE,
+                stderr=subprocess.PIPE,
+                env=env,
+                timeout=SHORT_TIMEOUT,
+            )
+
+    @unittest.skipUnless(pty, "requires pty")
+    def test_asyncio_repl_is_ok(self):
+        m, s = pty.openpty()
+        cmd = [sys.executable, "-m", "asyncio"]
+        proc = subprocess.Popen(
+            cmd,
+            stdin=s,
+            stdout=s,
+            stderr=s,
+            text=True,
+            close_fds=True,
+            env=os.environ,
+        )
+        os.close(s)
+        os.write(m, b"await asyncio.sleep(0)\n")
+        os.write(m, b"exit()\n")
+        output = []
+        while select.select([m], [], [], SHORT_TIMEOUT)[0]:
+            try:
+                data = os.read(m, 1024).decode("utf-8")
+                if not data:
+                    break
+            except OSError:
+                break
+            output.append(data)
+        os.close(m)
+        try:
+            exit_code = proc.wait(timeout=SHORT_TIMEOUT)
+        except subprocess.TimeoutExpired:
+            proc.kill()
+            exit_code = proc.wait()
+
+        self.assertEqual(exit_code, 0)
 
 class TestInteractiveModeSyntaxErrors(unittest.TestCase):