From: Stephen Leake <stephen_leake@stephe-leake.org>
Subject: Re: Float conversion
Date: Thu, 05 Aug 2010 08:05:07 -0400
Date: 2010-08-05T08:05:07-04:00 [thread overview]
Message-ID: <82vd7ps1sc.fsf@stephe-leake.org> (raw)
In-Reply-To: wcctynay1yf.fsf@shell01.TheWorld.com
Robert A Duff <bobduff@shell01.TheWorld.com> writes:
> Stephen Leake <stephen_leake@stephe-leake.org> writes:
>
>> Phil Clayton <phil.clayton@lineone.net> writes:
>>
>>> On Jul 31, 4:12 pm, Stephen Leake <stephen_le...@stephe-leake.org>
>>> wrote:
>>>> Clearly to cover all cases, you
>>>> need A < B, A = B, A > B, A < C, etc.
>>>
>>> You make it sound easy...
>>
>> It is easy! This is a very small program; exhaustive testing is
>> appropriate.
>
> I wouldn't call that "exhaustive". To me, exhaustive testing means
> testing every possible input. There are far more than 9.
Yes, that's true.
> You seem to be using some sort of coverage metric, not exhaustive
> testing.
Yes.
>> According to the code, there are three important edge cases for each
>> pair: A < B, A = B, A > B
>
> I don't understand that. Phil Clayton's example was:
>
> if A < B and A < C
> then
> Y := A;
> elsif B < C and B < A
> then
> Y := B;
> else
> Y := C;
> end if;
>
> (Interesting example, by the way!)
I was talking about my rewrite, which got rid of the 'and' operators to
make things clearer.
> And why not A=B-epsilon?
That's one appropriate test case for A < B, along with A = B - 1.0.
> By the way, putting:
>
> pragma Assert (C < B and C < A);
>
> after "else" might have made the bug clearer. Or might not.
That's a good idea.
>> What are you verifying, if not a specification?
>
> You can't formally verify specifications. You can (sometimes) formally
> verify that the code matches a specification.
That's what I meant; the verification process is meaningless without a
specification.
--
-- Stephe
next prev parent reply other threads:[~2010-08-05 12:05 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-07-29 12:23 Float conversion Henrique
2010-07-29 12:44 ` Jacob Sparre Andersen
2010-07-29 12:46 ` Dmitry A. Kazakov
2010-07-29 15:08 ` Georg Bauhaus
2010-07-29 15:10 ` Georg Bauhaus
2010-07-29 15:35 ` Dmitry A. Kazakov
2010-07-29 18:21 ` Henrique
2010-07-29 19:08 ` Jeffrey R. Carter
2010-07-29 19:15 ` Dmitry A. Kazakov
2010-07-30 1:30 ` Phil Clayton
2010-07-30 8:43 ` Dmitry A. Kazakov
2010-07-30 13:14 ` Phil Clayton
2010-07-30 14:34 ` Dmitry A. Kazakov
2010-07-31 15:12 ` Stephen Leake
2010-08-03 1:07 ` Phil Clayton
2010-08-03 3:31 ` Shark8
2010-08-03 10:38 ` Georg Bauhaus
2010-08-04 7:27 ` Stephen Leake
2010-08-04 16:15 ` Georg Bauhaus
2010-08-04 16:32 ` Phil Clayton
2010-08-04 7:26 ` Stephen Leake
2010-08-04 12:52 ` Robert A Duff
2010-08-04 14:32 ` Dmitry A. Kazakov
2010-08-04 19:36 ` Simon Wright
2010-08-04 19:46 ` Dmitry A. Kazakov
2010-08-04 20:29 ` Georg Bauhaus
2010-08-05 12:05 ` Stephen Leake [this message]
2010-08-07 5:54 ` Shark8
2010-08-07 8:56 ` Georg Bauhaus
2010-08-07 13:49 ` Shark8
2010-08-05 10:20 ` Phil Clayton
2010-07-30 13:16 ` Henrique
2010-07-29 15:37 ` Warren
2010-07-29 14:56 ` Georg Bauhaus
2010-07-29 17:56 ` Jeffrey R. Carter
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