[PATCH v2] shlwapi/tests: Document where SHFormatDateTimeA() crashes for NULL pointers.

[Saulius Krasuckas]

* On 2021-09-02 12:13, Huw Davies wrote:
> On Thu, Sep 02, 2021 at 11:44:36AM +0300, Saulius Krasuckas wrote:
>> I mean, if some questions arises about when that input pointer is 
>> handled
>> (before other argument validation or maybe after that, or maybe at the 
>> end),
>> the crash (and maybe additional crashes) would give some insights 
>> about the
>> original algorithm.
> 
> Which is exactly why you should *not* write these sort of tests.

Huw, I disagree that there can be a wrong sort of tests in black-box 
testing. Really don't see this.

> We're aiming to match the functionality of the API without copying its
> implementation.  We don't want to know about its internal branching
> structure.

And I aim at the functionality too: not the implementation, but the 
exactness of the behavior.

IMO, it would be quite difficult to always ensure the project does the 
same function in the very different way. Difficult to prove and 
unnecessary. Because this is a black-box. Do I get this wrong?

Plus, in case a developer starts being afraid that one or another test 
would reveal some unavoidable details of the original 
function/algorithm, one could quickly get lost in the doubt and start 
dropping every second ok-check in the area.  Which would be a disaster 
for a black-box testing.

I don't think these two things can be easily decoupled (even if the 
original implementation goes open source, even with the compatible 
license) or is it necessary at all. Just a PoV.

> Of course if a particular app depends on Windows returning a specific
> error code then thats the time to add a test for it.

OK. And leaving the disabled test code only helps to do that (for 
everyone in doubt).
I still saw no harm in that code.

S.

PS. As the removal patch already got accepted, I hope no one minds my 
response. :)