[Python-Dev] cpython (2.7): Fix memory error in test_ucn.

[Antoine Pitrou]

On Mon, 21 Jan 2013 12:06:25 +0100 (CET)
serhiy.storchaka <python-checkins at python.org> wrote:
> diff --git a/Lib/test/test_ucn.py b/Lib/test/test_ucn.py
> --- a/Lib/test/test_ucn.py
> +++ b/Lib/test/test_ucn.py
> @@ -144,13 +144,14 @@
>          # very very long bogus character name
>          try:
>              x = b'\\N{SPACE' + b'x' * int(_testcapi.UINT_MAX + 1) + b'}'
> +            self.assertEqual(len(x), len(b'\\N{SPACE}') +
> +                                     (_testcapi.UINT_MAX + 1))
> +            self.assertRaisesRegexp(UnicodeError,
> +                'unknown Unicode character name',
> +                x.decode, 'unicode-escape'
> +            )
>          except MemoryError:
>              raise unittest.SkipTest("not enough memory")
> -        self.assertEqual(len(x), len(b'\\N{SPACE}') + (_testcapi.UINT_MAX + 1))
> -        self.assertRaisesRegexp(UnicodeError,
> -            'unknown Unicode character name',
> -            x.decode, 'unicode-escape'
> -        )

You can't just do that. The test may end up swapping a lot and make the
machine grind to a halt, rather than raise MemoryError. This threatens
to make life miserable for anyone who hasn't enough RAM, but has enough
swap to fit the test's working set.

Really, you have to use a bigmem decorator.

Regards

Antoine.