RE: [PATCH v3 kunit-next 1/2] kunit: add debugfs /sys/kernel/debug/kunit/<suite>/results display

[Bird, Tim]

> -----Original Message-----
> From:  Brendan Higgins
> 
> On Wed, Feb 12, 2020 at 7:25 PM Frank Rowand <frowand.list@xxxxxxxxx> wrote:
> >
> > On 2/7/20 10:58 AM, Alan Maguire wrote:

...

> > > diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> > > index 9242f93..aec607f 100644
> > > --- a/lib/kunit/test.c
> > > +++ b/lib/kunit/test.c
> > > @@ -10,6 +10,7 @@
> > >  #include <linux/kernel.h>
> > >  #include <linux/sched/debug.h>
> > >
> > > +#include "debugfs.h"
> > >  #include "string-stream.h"
> > >  #include "try-catch-impl.h"
> > >
> > > @@ -28,73 +29,91 @@ static void kunit_print_tap_version(void)
> > >       }
> > >  }
> > >
> > > -static size_t kunit_test_cases_len(struct kunit_case *test_cases)
> > > +size_t kunit_suite_num_test_cases(struct kunit_suite *suite)
> > >  {
> > >       struct kunit_case *test_case;
> > >       size_t len = 0;
> > >
> > > -     for (test_case = test_cases; test_case->run_case; test_case++)
> > > +     kunit_suite_for_each_test_case(suite, test_case)
> > >               len++;
> > >
> > >       return len;
> > >  }
> > > +EXPORT_SYMBOL_GPL(kunit_suite_num_test_cases);
> > >
> > >  static void kunit_print_subtest_start(struct kunit_suite *suite)
> > >  {
> > >       kunit_print_tap_version();
> > > -     pr_info("\t# Subtest: %s\n", suite->name);
> > > -     pr_info("\t1..%zd\n", kunit_test_cases_len(suite->test_cases));
> > > +     kunit_log(KERN_INFO, suite, "# Subtest: %s", suite->name);
> > > +     kunit_log(KERN_INFO, suite, "1..%zd",
> > > +               kunit_suite_num_test_cases(suite));
> >
> > The subtest 'is a TAP stream indented 4 spaces'.  (So the old code was
> > also incorrect since it indented with a tab.)
> 
> Whoops.
> 
> I agree that fixing tabs to spaces is probably the easiest thing to do
> here; nevertheless, I think this might be a good time to talk about
> other deviations from the spec and what to do about it. This might
> also be a good time to bring up Tim's comment at LPC last year about
> forking TAP. Arguably I already have given that TAP14 is still under
> review and is consequently subject to change.
> 
> Additionally, the way I report expectation/assertion failures are my
> own extension to the TAP spec. I did this because at the time I wasn't
> ready to open the can of worms that was adding a YAML serializer to
> the Linux kernel; I mentioned adding a YAML serializer at LPC and
> people didn't seem super thrilled with the idea.

I'm not sure I follow.  Are you talking about writing YAML or interpreting
YAML.  You don't need a serializer to write YAML.  It can be done 
with straight text output.  I guess it depends on the scope of what you
envision.  Even if you want to do more than trivial structured output,
I don't think you'll need a full serializer.  (IOW, I think you could sneak
something in and just call it a test output formatter.  Just don't call it YAML
and most people won't notice. :-)

> 
> Further both the TAP implementation here as well as what is in
> kselftest have arbitrary kernel output mixed in with TAP output, which
> seems to be a further deviation from the spec.
Well that's a different kettle of worms, and really argues for staying
with something that is strictly line-based.

> 
> In an effort to do this, and so that at the very least I could
> document what I have done here, I have been looking into getting a
> copy of TAP into the kernel. Unfortunately, TAP appears to have some
> licensing issues. TAP says that it can be used/modified "under the
> same terms as Perl itself" and then provides a dead link. I filed a
> pull request to update the licence to the Perl Artistic Licence 1.0
> since I believe that is what they are referencing; however, I have not
> heard back from them yet.

When you say "getting a copy of TAP into the kernel", I presume you mean
an existing implementation to produce TAP output?  Or are you talking about
a TAP interpreter?  I'm not sure the former needs to use an existing implementation.

I previously volunteered (in Lisbon) to write up the TAP deviations,
and never got around to it.   Sorry about that. I can try to work on it now if
people are still interested.
 -- Tim

[rest of patch omitted]