On Fri, May 10, 2019 at 5:13 AM Knut Omang <knut.omang@xxxxxxxxxx> wrote: > On Fri, 2019-05-10 at 03:23 -0700, Brendan Higgins wrote: > > > On Fri, May 10, 2019 at 7:49 AM Knut Omang <knut.omang@xxxxxxxxxx> wrote: > > > > > > > > On Thu, 2019-05-09 at 22:18 -0700, Frank Rowand wrote: > > > > > On 5/9/19 4:40 PM, Logan Gunthorpe wrote: > > > > > > > > > > > > > > > > > > On 2019-05-09 5:30 p.m., Theodore Ts'o wrote: > > > > > >> On Thu, May 09, 2019 at 04:20:05PM -0600, Logan Gunthorpe wrote: > > > > > >>> > > > > > >>> The second item, arguably, does have significant overlap with kselftest. > > > > > >>> Whether you are running short tests in a light weight UML environment or > > > > > >>> higher level tests in an heavier VM the two could be using the same > > > > > >>> framework for writing or defining in-kernel tests. It *may* also be valuable > > > > > >>> for some people to be able to run all the UML tests in the heavy VM > > > > > >>> environment along side other higher level tests. > > > > > >>> > > > > > >>> Looking at the selftests tree in the repo, we already have similar items to > > > > > >>> what Kunit is adding as I described in point (2) above. kselftest_harness.h > > > > > >>> contains macros like EXPECT_* and ASSERT_* with very similar intentions to > > > > > >>> the new KUNIT_EXECPT_* and KUNIT_ASSERT_* macros. > > > > > >>> > > > > > >>> However, the number of users of this harness appears to be quite small. Most > > > > > >>> of the code in the selftests tree seems to be a random mismash of scripts > > > > > >>> and userspace code so it's not hard to see it as something completely > > > > > >>> different from the new Kunit: > > > > > >>> > > > > > >>> $ git grep --files-with-matches kselftest_harness.h * > > > > > >> > > > > > >> To the extent that we can unify how tests are written, I agree that > > > > > >> this would be a good thing. However, you should note that > > > > > >> kselftest_harness.h is currently assums that it will be included in > > > > > >> userspace programs. This is most obviously seen if you look closely > > > > > >> at the functions defined in the header files which makes calls to > > > > > >> fork(), abort() and fprintf(). > > > > > > > > > > > > Ah, yes. I obviously did not dig deep enough. Using kunit for > > > > > > in-kernel tests and kselftest_harness for userspace tests seems like > > > > > > a sensible line to draw to me. Trying to unify kernel and userspace > > > > > > here sounds like it could be difficult so it's probably not worth > > > > > > forcing the issue unless someone wants to do some really fancy work > > > > > > to get it done. > > > > > > > > > > > > Based on some of the other commenters, I was under the impression > > > > > > that kselftests had in-kernel tests but I'm not sure where or if they > > > > > > exist. > > > > > > > > > > YES, kselftest has in-kernel tests. (Excuse the shouting...) > > > > > > > > > > Here is a likely list of them in the kernel source tree: > > > > > > > > > > $ grep module_init lib/test_*.c > > > > > lib/test_bitfield.c:module_init(test_bitfields) > > > > > lib/test_bitmap.c:module_init(test_bitmap_init); > > > > > lib/test_bpf.c:module_init(test_bpf_init); > > > > > lib/test_debug_virtual.c:module_init(test_debug_virtual_init); > > > > > lib/test_firmware.c:module_init(test_firmware_init); > > > > > lib/test_hash.c:module_init(test_hash_init); /* Does everything */ > > > > > lib/test_hexdump.c:module_init(test_hexdump_init); > > > > > lib/test_ida.c:module_init(ida_checks); > > > > > lib/test_kasan.c:module_init(kmalloc_tests_init); > > > > > lib/test_list_sort.c:module_init(list_sort_test); > > > > > lib/test_memcat_p.c:module_init(test_memcat_p_init); > > > > > lib/test_module.c:static int __init test_module_init(void) > > > > > lib/test_module.c:module_init(test_module_init); > > > > > lib/test_objagg.c:module_init(test_objagg_init); > > > > > lib/test_overflow.c:static int __init test_module_init(void) > > > > > lib/test_overflow.c:module_init(test_module_init); > > > > > lib/test_parman.c:module_init(test_parman_init); > > > > > lib/test_printf.c:module_init(test_printf_init); > > > > > lib/test_rhashtable.c:module_init(test_rht_init); > > > > > lib/test_siphash.c:module_init(siphash_test_init); > > > > > lib/test_sort.c:module_init(test_sort_init); > > > > > lib/test_stackinit.c:module_init(test_stackinit_init); > > > > > lib/test_static_key_base.c:module_init(test_static_key_base_init); > > > > > lib/test_static_keys.c:module_init(test_static_key_init); > > > > > lib/test_string.c:module_init(string_selftest_init); > > > > > lib/test_ubsan.c:module_init(test_ubsan_init); > > > > > lib/test_user_copy.c:module_init(test_user_copy_init); > > > > > lib/test_uuid.c:module_init(test_uuid_init); > > > > > lib/test_vmalloc.c:module_init(vmalloc_test_init) > > > > > lib/test_xarray.c:module_init(xarray_checks); > > > > > > > > > > > > > > > > If they do exists, it seems like it would make sense to > > > > > > convert those to kunit and have Kunit tests run-able in a VM or > > > > > > baremetal instance. > > > > > > > > > > They already run in a VM. > > > > > > > > > > They already run on bare metal. > > > > > > > > > > They already run in UML. > > > > > > > > > > This is not to say that KUnit does not make sense. But I'm still trying > > > > > to get a better description of the KUnit features (and there are > > > > > some). > > > > > > > > FYI, I have a master student who looks at converting some of these to KTF, such as > > for > > > > instance the XArray tests, which lended themselves quite good to a semi-automated > > > > conversion. > > > > > > > > The result is also a somewhat more compact code as well as the flexibility > > > > provided by the Googletest executor and the KTF frameworks, such as running selected > > > > tests, output formatting, debugging features etc. > > > > > > So is KTF already in upstream? Or is the plan to unify the KTF and > > > > I am not certain about KTF's upstream plans, but I assume that Knut > > would have CC'ed me on the thread if he had started working on it. > > You are on the Github watcher list for KTF? Yep! I have been since LPC in 2017. > Quite a few of the commits there are preparatory for a forthcoming kernel patch set. > I'll of course CC: you on the patch set when we send it to the list. Awesome! I appreciate it. > > > > Kunit in-kernel test harnesses? Because there's tons of these > > > > No, no plan. Knut and I talked about this a good while ago and it > > seemed that we had pretty fundamentally different approaches both in > > terms of implementation and end goal. Combining them seemed pretty > > infeasible, at least from a technical perspective. Anyway, I am sure > > Knut would like to give him perspective on the matter and I don't want > > to say too much without first giving him a chance to chime in on the > > matter. > > I need more time to study KUnit details to say, but from a 10k feet perspective: > I think at least there's a potential for some API unification, in using the same macro > names. How about removing the KUNIT_ prefix to the test macros ;-) ? Heh, heh. That's actually the way I had it in the earliest versions of KUnit! But that was pretty much the very first thing everyone complained about. I think I went from no prefix (like you are suggesting) to TEST_* before the first version of the RFC at the request of several people I was kicking the idea around with, and then I think I was asked to go from TEST_* to KUNIT_* in the very first revision of the RFC. In short, I am sympathetic to your suggestion, but I think that is non-negotiable at this point. The community has a clear policy in place on the matter, and at this point I would really prefer not to change all the symbol names again. > That would make the names shorter, saving typing when writing tests, and storage ;-) > and also make the names more similar to KTF's, and those of user land unit test You mean the Googletest/Googlemock expectations/assertions? It's a great library (with not so great a name), but unfortunately it is written in C++, which I think pretty much counts it out here. > frameworks? Also it will make it possible to have functions compiling both with KTF and > KUnit, facilitating moving code between the two. I think that would be cool, but again, I don't think this will be possible with Googletest/Googlemock. > > Also the string stream facilities of KUnit looks interesting to share. I am glad you think so! If your biggest concern on my side is test macro names (which I think is a no-go as I mentioned above), I think we should be in pretty good shape once you are ready to move forward. Besides, I have a lot more KUnit patches coming after this: landing this patchset is just the beginning. So how about we keep moving forward on this patchset?
