"Strong typing vs. strong testing"

Pascal J. Bourguignon pjb at informatimago.com
Thu Sep 30 22:20:20 CEST 2010


Ian Collins <ian-news at hotmail.com> writes:

> On 10/ 1/10 02:57 AM, Pascal Bourguignon wrote:
>> Nick Keighley<nick_keighley_nospam at hotmail.com>  writes:
>>
>>> On 27 Sep, 20:29, p... at informatimago.com (Pascal J. Bourguignon)
>>> wrote:
>>>> If you start with the mindset of static type checking, you will consider
>>>> that your types are checked and if the types at the interface of two
>>>> modules matches you'll think that everything's ok.  And six months later
>>>> you Mars mission will crash.
>>>
>>> do you have any evidence that this is actually so? That people who
>>> program in statically typed languages actually are prone to this "well
>>> it compiles so it must be right" attitude?
>>
>> Yes, I can witness that it's in the mind set.
>>
>> Well, the problem being always the same, the time pressures coming from
>> the sales people (who can sell products of which the first line of
>> specifications has not been written yet, much less of code), it's always
>> a battle to explain that once the code is written, there is still a lot
>> of time needed to run tests and debug it.  I've even technical managers,
>> who should know better, expecting that we write bug-free code in the
>> first place (when we didn't even have a specification to begin with!).
>
> Which is why agile practices such as TDD have an edge.  If it compiles
> *and* passes all its tests, it must be right.

Well, at least it passes the test.  I would like to see a peer reviewed
proof that the program is correct ;-)

But indeed tests are required in any case.
-- 
__Pascal Bourguignon__                     http://www.informatimago.com/



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