Re: Converting kselftest test modules to kunit

Shuah Khan
2024-07-26T19:35:03Z

On 7/15/24 04:09, Muhammad Usama Anjum wrote:
> Hi Kees and All,
>
> There are several tests in kselftest subsystem which load modules to tests
> the internals of the kernel. Most of these test modules are just loaded by
> the kselftest, their status isn't read and reported to the user logs. Hence
> they don't provide benefit of executing those tests.
>
> I've found patches from Kees where he has been converting such kselftests
> to kunit tests [1]. The probable motivation is to move tests output of
> kselftest subsystem which only triggers tests without correctly reporting
> the results. On the other hand, kunit is there to test the kernel's
> internal functions which can't be done by userspace.
>
> Kselftest: Test user facing APIs from userspace
> Kunit: Test kernel's internal functions from kernelspace
>
> This brings me to conclusion that kselftest which are loading modules to
> test kernelspace should be converted to kunit tests. I've noted several
> such kselftests.
>
> This is just my understanding. Please mention if I'm correct above or more
> reasons to support kselftest test modules transformation into kunit test.
>
> [1] https://lore.kernel.org/all/20221018082824.never.845-kees@kernel.org/
>

Please make sure you aren't taking away the ability to run these tests during
boot. It doesn't make sense to convert every single test especially when it
is intended to be run during boot without dependencies - not as a kunit test
but a regression test during boot.

bitmap is one example - pay attention to the config help test - bitmap
one clearly states it runs regression testing during boot. Any test that
says that isn't a candidate for conversion.

I am going to nack any such conversions.

thanks,
-- Shuah