Re: [PATCH 1/2] kunit: add parameter generation macro using description from array

From: "Berg, Benjamin" <benjamin.berg@intel.com>
To: "davidgow@google.com" <davidgow@google.com>
Cc: "linux-kselftest@vger.kernel.org"
	<linux-kselftest@vger.kernel.org>,
	"kunit-dev@googlegroups.com" <kunit-dev@googlegroups.com>
Subject: Re: [PATCH 1/2] kunit: add parameter generation macro using description from array
Date: Wed, 6 Sep 2023 07:04:56 +0000	[thread overview]
Message-ID: <fb555599ae74a52d4b4ef59c9fbd8214179be5d6.camel@intel.com> (raw)
In-Reply-To: <CABVgOSkvVX3D-fgmO-w6eJm7fxQL1T-tVJ6oMVQVhEn98Bmdqw@mail.gmail.com>

Hi,

On Wed, 2023-09-06 at 14:45 +0800, David Gow wrote:
> On Mon, 4 Sept 2023 at 21:22, <benjamin@sipsolutions.net> wrote:
> > 
> > From: Benjamin Berg <benjamin.berg@intel.com>
> > 
> > The existing KUNIT_ARRAY_PARAM macro requires a separate function
> > to
> > get the description. However, in a lot of cases the description can
> > just be copied directly from the array. Add a second macro that
> > avoids having to write a static function just for a single strscpy.
> > 
> > Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>
> > ---
> 
> Looks good to me: this will be much more convenient. The actual
> implementation looks spot on, just a small comment about the
> documentation change.
> 
> It may make sense to write some tests and/or some follow-up patches to
> existing tests to use this macro, too. I'm just a little wary of
> introducing something totally unused. (I'm happy to do these myself if
> you don't have time, though.)

I agree. I am happy to submit one or more patches to change the
existing users. The question would be how we pull such a change in.
Should it be submitted separately for each subtree or can we pull them
all in at the same time here?

Benjamin

> 
> Regardless, with the documentation fix, this is:
> Reviewed-by: David Gow <davidgow@google.com>
> 
> Cheers,
> -- David
> 
> >  Documentation/dev-tools/kunit/usage.rst |  7 ++++---
> >  include/kunit/test.h                    | 19 +++++++++++++++++++
> >  2 files changed, 23 insertions(+), 3 deletions(-)
> > 
> > diff --git a/Documentation/dev-tools/kunit/usage.rst
> > b/Documentation/dev-tools/kunit/usage.rst
> > index c27e1646ecd9..fe8c28d66dfe 100644
> > --- a/Documentation/dev-tools/kunit/usage.rst
> > +++ b/Documentation/dev-tools/kunit/usage.rst
> > @@ -571,8 +571,9 @@ By reusing the same ``cases`` array from above,
> > we can write the test as a
> >         {
> >                 strcpy(desc, t->str);
> >         }
> > -       // Creates `sha1_gen_params()` to iterate over `cases`.
> > -       KUNIT_ARRAY_PARAM(sha1, cases, case_to_desc);
> > +       // Creates `sha1_gen_params()` to iterate over `cases`
> > while using
> > +       // the struct member `str` for the case description.
> > +       KUNIT_ARRAY_PARAM_DESC(sha1, cases, str);
> 
> I'd suggest either getting rid of the case_to_desc function totally
> here, or show both the manual KUNIT_ARRAY_PARAM() example, and then
> point out explicitly that KUNIT_ARRAY_PARAM_DESC() can replace it.
> 
> Otherwise we end up with a vestigial function which doesn't do
> anything and is confusing.
> 
> 
> > 
> >         // Looks no different from a normal test.
> >         static void sha1_test(struct kunit *test)
> > @@ -588,7 +589,7 @@ By reusing the same ``cases`` array from above,
> > we can write the test as a
> >         }
> > 
> >         // Instead of KUNIT_CASE, we use KUNIT_CASE_PARAM and pass
> > in the
> > -       // function declared by KUNIT_ARRAY_PARAM.
> > +       // function declared by KUNIT_ARRAY_PARAM or
> > KUNIT_ARRAY_PARAM_DESC.
> >         static struct kunit_case sha1_test_cases[] = {
> >                 KUNIT_CASE_PARAM(sha1_test, sha1_gen_params),
> >                 {}
> > diff --git a/include/kunit/test.h b/include/kunit/test.h
> > index 68ff01aee244..f60d11e41855 100644
> > --- a/include/kunit/test.h
> > +++ b/include/kunit/test.h
> > @@ -1516,6 +1516,25 @@ do
> > {                                                                  
> >           \
> >                 return
> > NULL;                                                              
> >       \
> >         }
> > 
> > +/**
> > + * KUNIT_ARRAY_PARAM_DESC() - Define test parameter generator from
> > an array.
> > + * @name:  prefix for the test parameter generator function.
> > + * @array: array of test parameters.
> > + * @desc_member: structure member from array element to use as
> > description
> > + *
> > + * Define function @name_gen_params which uses @array to generate
> > parameters.
> > + */
> > +#define KUNIT_ARRAY_PARAM_DESC(name, array,
> > desc_member)                                       \
> > +       static const void *name##_gen_params(const void *prev, char
> > *desc)                      \
> > +      
> > {                                                                  
> >                      \
> > +               typeof((array)[0]) *__next = prev ?
> > ((typeof(__next)) prev) + 1 : (array);      \
> > +               if (__next - (array) < ARRAY_SIZE((array)))
> > {                                   \
> > +                       strscpy(desc, __next->desc_member,
> > KUNIT_PARAM_DESC_SIZE);              \
> > +                       return
> > __next;                                                          \
> > +              
> > }                                                                  
> >              \
> > +               return
> > NULL;                                                              
> >       \
> > +       }
> > +
> >  // TODO(dlatypov@google.com): consider eventually migrating users
> > to explicitly
> >  // include resource.h themselves if they need it.
> >  #include <kunit/resource.h>
> > --
> > 2.41.0
> > 
> > --
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> > Groups "KUnit Development" group.
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> > To view this discussion on the web visit
> > https://groups.google.com/d/msgid/kunit-dev/20230904132139.103140-1-benjamin%40sipsolutions.net
> > .

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