[PATCH v3 4/6] ntoskrnl.exe/tests: Add some HidP_Get*Caps tests.

[Rémi Bernon]

On 6/8/21 11:27 PM, Zebediah Figura (she/her) wrote:
> On 6/8/21 4:10 PM, Rémi Bernon wrote:
>> On 6/8/21 10:59 PM, Zebediah Figura (she/her) wrote:
>>>> exp->NumberFeatureDataIndices, "unexpected caps 
>>>> NumberFeatureDataIndices %d, expected %d\n", 
>>>> caps->NumberFeatureDataIndices, exp->NumberFeatureDataIndices);
>>>> +}
>>>
>>> These are some *really* long lines, and same with the ones below.
>>>
>>> I guess it's always nice to see what exactly differs, but maybe it's 
>>> more worthwhile just to use memcmp()? I don't feel strongly about it, 
>>> though.
>>>
>>
>> I think memcmp is fine up to the moment where the test breaks. To 
>> debug the issue it's nice to see what didn't match without having to 
>> write those long lines yourself (same for debugstr BTW, I'd love to 
>> have more helpers to dump the various Win32 structs readily available).
>>
>> And for instance I don't like the report memcmp very much, because it 
>> doesn't tell you at all what's wrong with HidP_InitializeReportForID.
>>
>> This only needs to be written once and (hopefully) nobody will have to 
>> look at it again. But then you can use it to check that both struct 
>> match and have precise info when they don't.
>>
>> I would have like to be able to put individual todo_wine to replace 
>> the additional tests for the partially matching structs, but it was 
>> not convenient, so instead I'm just going to replace all the checks 
>> with a single call to these functions when the todo_wine are fixed.
> 
> Yeah, though on the other hand that's one reason it's nice to use memcmp 
> - either they match or they don't.
> 
> Just a bit of extra 2¢: in DirectShow I ended up using memcmp() to match 
> AM_MEDIA_TYPE. If a test breaks, which is not infrequently, I 
> temporarily add strmbase_dump_media_type() to check the difference. 
> Actually I've considered adding an automatic helper like that to 
> compare_media_types() everywhere, though it'd be nice to have a 
> debugstr_* type helper instead so that I don't have to turn on +strmbase 
> to use it.
> 
> It may be a nice approach in general to structure things like
> 
> static bool compare_some_struct(const SOME_STRUCT *s, const SOME_STRUCT 
> *expect)
> {
>     if (!memcmp(s, expect, sizeof(*SOME_STRUCT)))
>         return true;
>     trace("Expected: %s\n", debugstr_some_struct(expect));
>     trace("Received: %s\n", debugstr_some_struct(s));
> }
> 
> ...
> 
> {
>     ok(compare_some_struct(&s, &expect), "Structures didn't match.\n");
> }
> 

I don't have good opinion of trace-ing failures, I find that it quickly 
gets cut, and in general the traces you were interested it are after the 
cut.
-- 
Rémi Bernon <rbernon at codeweavers.com>