Re: [PATCH v18 00/19] kunit: introduce KUnit, the Linux kernel unit testing framework

From: shuah
Date: Mon Oct 07 2019 - 10:42:57 EST


On 10/7/19 2:40 AM, Brendan Higgins wrote:
On Sun, Oct 6, 2019 at 10:18 AM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

On Sun, Oct 6, 2019 at 9:55 AM Theodore Y. Ts'o <tytso@xxxxxxx> wrote:

Well, one thing we *can* do is if (a) if we can create a kselftest
branch which we know is stable and won't change, and (b) we can get
assurances that Linus *will* accept that branch during the next merge
window, those subsystems which want to use kself test can simply pull
it into their tree.

Yes.

At the same time, I don't think it needs to be even that fancy. Even
if it's not a stable branch that gets shared between different
developers, it would be good to just have people do a "let's try this"
throw-away branch to use the kunit functionality and verify that
"yeah, this is fairly convenient for ext4".

It doesn't have to be merged in that form, but just confirmation that
the infrastructure is helpful before it gets merged would be good.

I thought we already had done this satisfactorily.

Adding a couple more tests will only help in the long run. The idea is
to see can this help

We have one proof-of-concept test in the branch in the kselftest repo
(proc sysctl test) that went out in the pull request, and we also had
some other tests that were not in the pull request (there is the ext4
timestamp stuff mentioned above, and we also had one against the list
data structure), which we were planning on sending out for review once
Shuah's pull request was accepted. I know the apparmor people also
wrote some tests that they said were useful; however, I have not
coordinated with them on upstreaming their tests. I know of some other
people who are using it, but I don't think the tests are as far along
for upstreaming.


Maybe that is a good start. To get the tests that are already in use
and get them in shape for upstream.

The point is: I thought we had plenty of signal that KUnit would be
useful to have merged into the mainline kernel. I thought the only
reason it was rejected for 5.4 was due to the directory name issue
combined with bad timing.


That is probably the initial thought. However, it makes perfect sense
to add a couple of tests in. We have a few weeks anyway and it gives
us more confidence on kunit.

I already have a branch that is in linux-next and it just has kunit in
it and I will rebase it to 5.4-rc1.

https://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest.git/log/?h=test

Let's use that for kunit work for 5.5. I won't add any kselftest patches
to it and keep it dedicated for kunit work. When tests are ready for
upstream, I can keep adding them to this branch.

thanks,
-- Shuah