test_gc.py 文件源码

def test_garbage_at_shutdown(self):
        import subprocess
        code = """if 1:
            import gc
            import _testcapi
            @_testcapi.with_tp_del
            class X:
                def __init__(self, name):
                    self.name = name
                def __repr__(self):
                    return "<X %%r>" %% self.name
                def __tp_del__(self):
                    pass

            x = X('first')
            x.x = x
            x.y = X('second')
            del x
            gc.set_debug(%s)
        """
        def run_command(code):
            p = subprocess.Popen([sys.executable, "-Wd", "-c", code],
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE)
            stdout, stderr = p.communicate()
            p.stdout.close()
            p.stderr.close()
            self.assertEqual(p.returncode, 0)
            self.assertEqual(stdout.strip(), b"")
            return strip_python_stderr(stderr)

        stderr = run_command(code % "0")
        self.assertIn(b"ResourceWarning: gc: 2 uncollectable objects at "
                      b"shutdown; use", stderr)
        self.assertNotIn(b"<X 'first'>", stderr)
        # With DEBUG_UNCOLLECTABLE, the garbage list gets printed
        stderr = run_command(code % "gc.DEBUG_UNCOLLECTABLE")
        self.assertIn(b"ResourceWarning: gc: 2 uncollectable objects at "
                      b"shutdown", stderr)
        self.assertTrue(
            (b"[<X 'first'>, <X 'second'>]" in stderr) or
            (b"[<X 'second'>, <X 'first'>]" in stderr), stderr)
        # With DEBUG_SAVEALL, no additional message should get printed
        # (because gc.garbage also contains normally reclaimable cyclic
        # references, and its elements get printed at runtime anyway).
        stderr = run_command(code % "gc.DEBUG_SAVEALL")
        self.assertNotIn(b"uncollectable objects at shutdown", stderr)