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

[Brendan Higgins]

On Fri, Oct 04, 2019 at 03:59:10PM -0600, shuah wrote:
> On 10/4/19 3:42 PM, Linus Torvalds wrote:
> > On Fri, Oct 4, 2019 at 2:39 PM Theodore Y. Ts'o <tytso@xxxxxxx> wrote:
> > > 
> > > This question is primarily directed at Shuah and Linus....
> > > 
> > > What's the current status of the kunit series now that Brendan has
> > > moved it out of the top-level kunit directory as Linus has requested?
> > 
> 
> The move happened smack in the middle of merge window and landed in
> linux-next towards the end of the merge window.
> 
> > We seemed to decide to just wait for 5.5, but there is nothing that
> > looks to block that. And I encouraged Shuah to find more kunit cases
> > for when it _does_ get merged.
> > 
> 
> Right. I communicated that to Brendan that we could work on adding more
> kunit based tests which would help get more mileage on the kunit.
> 
> > So if the kunit branch is stable, and people want to start using it
> > for their unit tests, then I think that would be a good idea, and then
> > during the 5.5 merge window we'll not just get the infrastructure,
> > we'll get a few more users too and not just examples.

I was planning on holding off on accepting more tests/changes until
KUnit is in torvalds/master. As much as I would like to go around
promoting it, I don't really want to promote too much complexity in a
non-upstream branch before getting it upstream because I don't want to
risk adding something that might cause it to get rejected again.

To be clear, I can understand from your perspective why getting more
tests/usage before accepting it is a good thing. The more people that
play around with it, the more likely that someone will find an issue
with it, and more likely that what is accepted into torvalds/master is
of high quality.

However, if I encourage arbitrary tests/improvements into my KUnit
branch, it further diverges away from torvalds/master, and is more
likely that there will be a merge conflict or issue that is not related
to the core KUnit changes that will cause the whole thing to be
rejected again in v5.5.

I don't know. I guess we could maybe address that situation by splitting
up the pull request into features and tests when we go to send it in,
but that seems to invite a lot of unnecessary complexity. I actually
already had some other tests/changes ready to send for review, but was
holding off until the initial set of patches mad it in.

Looking forward to hearing other people's thoughts.