test_sys.py 文件源码

def test_original_displayhook(self):
        import __builtin__
        savestdout = sys.stdout
        out = cStringIO.StringIO()
        sys.stdout = out

        dh = sys.__displayhook__

        self.assertRaises(TypeError, dh)
        if hasattr(__builtin__, "_"):
            del __builtin__._

        dh(None)
        self.assertEqual(out.getvalue(), "")
        self.assertTrue(not hasattr(__builtin__, "_"))
        dh(42)
        self.assertEqual(out.getvalue(), "42\n")
        self.assertEqual(__builtin__._, 42)

        del sys.stdout
        self.assertRaises(RuntimeError, dh, 42)

        sys.stdout = savestdout