Re: [RFC v4 00/17] kunit: introduce KUnit, the Linux kernel unit testing framework

[Frank Rowand <frowand.list@gmail.com>]

On 3/21/19 4:33 PM, Brendan Higgins wrote:
> On Thu, Mar 21, 2019 at 3:27 PM Logan Gunthorpe <logang@deltatee.com> wrote:
>>
>>
>>
>> On 2019-03-21 4:07 p.m., Brendan Higgins wrote:
>>> A couple of points, as for needing CONFIG_PCI; my plan to deal with
>>> that type of thing has been that we would add support for a KUnit/UML
>>> version that is just for KUnit. It would mock out the necessary bits
>>> to provide a fake hardware implementation for anything that might
>>> depend on it. I wrote a prototype for mocking/faking MMIO that I
>>> presented to the list here[1]; it is not part of the current patchset
>>> because we decided it would be best to focus on getting an MVP in, but
>>> I plan on bringing it back up at some point. Anyway, what do you
>>> generally think of this approach?
>>
>> Yes, I was wondering if that might be possible. I think that's a great
>> approach but it will unfortunately take a lot of work before larger
>> swaths of the kernel are testable in Kunit with UML. Having more common
>> mocked infrastructure will be great by-product of it though.
> 
> Yeah, it's unfortunate that the best way to do something often takes
> so much longer.
> 
>>
>>> Awesome, I looked at the code you posted and it doesn't look like you
>>> have had too many troubles. One thing that stood out to me, why did
>>> you need to put it in the kunit/ dir?
>>
>> Yeah, writing the code was super easy. Only after, did I realized I
>> couldn't get it to easily build.
> 
> Yeah, we really need to fix that; unfortunately, broadly addressing
> that problem is really hard and will most likely take a long time.
> 
>>
>> Putting it in the kunit directory was necessary because nothing in the
>> NTB tree builds unless CONFIG_NTB is set (see drivers/Makefile) and
>> CONFIG_NTB depends on CONFIG_PCI. I didn't experiment to see how hard it
>> would be to set CONFIG_NTB without CONFIG_PCI; I assumed it would be tricky.
>>
>>> I am looking forward to see what you think!
>>
>> Generally, I'm impressed and want to see this work in upstream as soon
>> as possible so I can start to make use of it!
> 
> Great to hear! I was trying to get the next revision out this week,
> but addressing some of the comments is taking a little longer than
> expected. I should have something together fairly soon though
> (hopefully next week). Good news is that next revision will be
> non-RFC; most of the feedback has settled down and I think we are
> ready to start figuring out how to merge it. Fingers crossed :-)
> 
> Cheers

I'll be out of the office next week and will not be able to review.
Please hold off on any devicetree related files until after I review.

Thanks,

Frank