Method test_nonexisting_with_pipes

Lib/test/test_subprocess.py:1495–1534

(self)

                                 stderr=subprocess.PIPE)

    def test_nonexisting_with_pipes(self):
        # bpo-30121: Popen with pipes must close properly pipes on error.
        # Previously, os.close() was called with a Windows handle which is not
        # a valid file descriptor.
        #
        # Run the test in a subprocess to control how the CRT reports errors
        # and to get stderr content.
        try:
            import msvcrt
            msvcrt.CrtSetReportMode
        except (AttributeError, ImportError):
            self.skipTest("need msvcrt.CrtSetReportMode")

        code = textwrap.dedent(f"""
            import msvcrt
            import subprocess

            cmd = {NONEXISTING_CMD!r}

            for report_type in [msvcrt.CRT_WARN,
                                msvcrt.CRT_ERROR,
                                msvcrt.CRT_ASSERT]:
                msvcrt.CrtSetReportMode(report_type, msvcrt.CRTDBG_MODE_FILE)
                msvcrt.CrtSetReportFile(report_type, msvcrt.CRTDBG_FILE_STDERR)

            try:
                subprocess.Popen(cmd,
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.PIPE)
            except OSError:
                pass
        """)
        cmd = [sys.executable, "-c", code]
        proc = subprocess.Popen(cmd,
                                stderr=subprocess.PIPE,
                                universal_newlines=True)
        with proc:
            stderr = proc.communicate()[1]
        self.assertEqual(stderr, "")
        self.assertEqual(proc.returncode, 0)

    def test_double_close_on_error(self):
        # Issue #18851