"Strong typing vs. strong testing"

Nick Keighley nick_keighley_nospam at hotmail.com
Sun Oct 17 15:12:22 CEST 2010


On 10 Oct, 10:44, Lie Ryan <lie.1... at gmail.com> wrote:
> On 10/02/10 20:04, NickKeighleywrote:


> >>> > > In a statically typed language, the of-the-wrong-type is something which
> >>> > > can, by definition, be caught at compile time.
>
> >> > Any time something is true "by definition" that is an indication that
> >> > it's not a particularly useful fact.
>
> > I'm not sure I agree. On occaision knowing something is true-by-
> > definition is very useful!
>
> Something that is true by definition is just as useful as saying: "my
> program is correct, by definition, because my requirement is what my
> code is doing".

well no it isn't. By definition a compiler catches (or is capable of
catching) type mismatches. And some (all?) type mismatches are a
useful diagnostic. You can dance around all you like but its true.

I've worked in a test department and I really have received "but
that's what the code says!" as an explanation for an observed
misbehaviour.


> It's a circular argument, your program requirement, for
> which the program is supposed to be tested against, is the code itself;
> so whatever undesirable behavior the program might have is parts of the
> requirement, so the program is, by definition, bug free and it's user
> expectation that's wrong.

yes I know. It's a strawman because I never said that or anything
resembling it.




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