From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Theodore Ts'o" Subject: Re: [PATCH v2 00/17] kunit: introduce KUnit, the Linux kernel unit testing framework Date: Wed, 8 May 2019 21:44:07 -0400 Message-ID: <20190509014407.GA7031@mit.edu> References: <20190501230126.229218-1-brendanhiggins@google.com> <54940124-50df-16ec-1a32-ad794ee05da7@gmail.com> <20190507080119.GB28121@kroah.com> <20190507172256.GB5900@mit.edu> <4d963cdc-1cbb-35a3-292c-552f865ed1f7@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <4d963cdc-1cbb-35a3-292c-552f865ed1f7-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Frank Rowand Cc: pmladek-IBi9RG/b67k@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, amir73il-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Brendan Higgins , dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, Alexander.Levin-0li6OtcxBFHby3iVrkZq2A@public.gmane.org, mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org, linux-kselftest-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, shuah-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, khilman-rdvid1DuHRBWk0Htik3J/w@public.gmane.org, knut.omang-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, kieran.bingham-ryLnwIuWjnjg/C1BVhZhaw@public.gmane.org, wfg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org, joel-U3u1mxZcP9KHXe+LvDLADg@public.gmane.org, rientjes-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, jdike-OPE4K8JWMJJBDgjK7y7TUQ@public.gmane.org, dan.carpenter-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kbuild-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Tim.Bird-7U/KSKJipcs@public.gmane.org, linux-um-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org, julia.lawall-L2FTfq7BK8M@public.gmane.org, kunit-dev-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org, richard-/L3Ra7n9ekc@public.gmane.org, sboyd-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Greg KH , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, mcgrof-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, daniel-/w4YWyX8dFk@public.gmane.org, keescook-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: devicetree@vger.kernel.org On Wed, May 08, 2019 at 05:58:49PM -0700, Frank Rowand wrote: > > If KUnit is added to the kernel, and a subsystem that I am submitting > code for has chosen to use KUnit instead of kselftest, then yes, I do > *have* to use KUnit if my submission needs to contain a test for the > code unless I want to convince the maintainer that somehow my case > is special and I prefer to use kselftest instead of KUnittest. That's going to be between you and the maintainer. Today, if you want to submit a substantive change to xfs or ext4, you're going to be asked to create test for that new feature using xfstests. It doesn't matter that xfstests isn't in the kernel --- if that's what is required by the maintainer. > > supposed to be a simple way to run a large number of small tests that > > for specific small components in a system. > > kselftest also supports running a subset of tests. That subset of tests > can also be a large number of small tests. There is nothing inherent > in KUnit vs kselftest in this regard, as far as I am aware. The big difference is that kselftests are driven by a C program that runs in userspace. Take a look at tools/testing/selftests/filesystem/dnotify_test.c it has a main(int argc, char *argv) function. In contrast, KUnit are fragments of C code which run in the kernel; not in userspace. This allows us to test internal functions inside complex file system (such as the block allocator in ext4) directly. This makes it *fundamentally* different from kselftest. Cheers, - Ted