Re: [PATCH 2/6] kunit: move check if assertion passed into the macros

[David Gow]

On Tue, Jan 11, 2022 at 6:33 AM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote:
>
> On Mon, Jan 10, 2022 at 2:21 PM Brendan Higgins
> <brendanhiggins@xxxxxxxxxx> wrote:
> >
> > On Fri, Jan 7, 2022 at 8:23 PM Daniel Latypov <dlatypov@xxxxxxxxxx> wrote:
> > >
> > > Currently the code always calls kunit_do_assertion() even though it does
> > > nothing when `pass` is true.
> > >
> > > This change moves the `if(!(pass))` check into the macro instead
> > > and renames the function to kunit_failed_assertion().
> > > I feel this a  bit easier to read and understand.
> > >
> > > This has the potential upside of avoiding a function call that does
> > > nothing most of the time (assuming your tests are passing) but comes
> > > with the downside of generating a bit more code and branches.
> > >
> > > This also means we don't have to initialize structs that we don't need,
> > > which will become a tiny bit more expensive if we switch over to using
> > > static variables to try and reduce stack usage. (There's runtime code
> > > to check if the variable has been initialized yet or not).
> > >
> > > Signed-off-by: Daniel Latypov <dlatypov@xxxxxxxxxx>
> >
> > Tiny nit, see below. Otherwise:
> >
> > Reviewed-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
> >
> > > ---
> > >  include/kunit/test.h | 20 ++++++++++----------
> > >  lib/kunit/test.c     | 13 ++++---------
> > >  2 files changed, 14 insertions(+), 19 deletions(-)
> > >
> > > diff --git a/include/kunit/test.h b/include/kunit/test.h
> > > index b26400731c02..690a28dfc795 100644
> > > --- a/include/kunit/test.h
> > > +++ b/include/kunit/test.h
> > > @@ -770,18 +770,18 @@ void __printf(2, 3) kunit_log_append(char *log, const char *fmt, ...);
> > >   */
> > >  #define KUNIT_SUCCEED(test) do {} while (0)
> > >
> > > -void kunit_do_assertion(struct kunit *test,
> > > -                       struct kunit_assert *assert,
> > > -                       bool pass,
> > > -                       const char *fmt, ...);
> > > +void kunit_failed_assertion(struct kunit *test,
> > > +                           struct kunit_assert *assert,
> > > +                           const char *fmt, ...);
> >
> > Tiny nit: I think this should be kunit_fail_assertion. I think
> > functions should be in the active tense, imperative mood since when
> > you call a function you are telling it to do something.
> >
> > Also, do we need to worry about this getting confused with KUNIT_FAIL,
> > or KUNIT_FAIL_ASSERTION:
>
> So do we want to try and pick a different name from
> kunit_fail_assertion() to avoid confusion with the macro?
> That's partly why I went with past tense.
> Perhaps: "kunit_do_assertion() => kunit_do_failed_assertion()" instead?

I'm not particularly picky about the name personally. But if I had to
join the bikeshedding, I'd probably go with kunit_assertion_fail() or
similar (kunit_assertion_failed works too, past-tense-wise.)

But kunit_do_fail{,ed}_assertion() would work too.


>
> Tangent: we have some similar confusing names, e.g. KUNIT_ASSERTION is
> both the name of a macro and an enum (kunit_assert_type), and those
> have the exact same case.
>
> >
> > https://elixir.bootlin.com/linux/v5.16/source/include/kunit/test.h#L788
> >
> > ?
> >
> > >  #define KUNIT_ASSERTION(test, pass, assert_class, INITIALIZER, fmt, ...) do {  \
> > > -       struct assert_class __assertion = INITIALIZER;                         \
> > > -       kunit_do_assertion(test,                                               \
> > > -                          &__assertion.assert,                                \
> > > -                          pass,                                               \
> > > -                          fmt,                                                \
> > > -                          ##__VA_ARGS__);                                     \
> > > +       if (!(pass)) {                                                         \
> > > +               struct assert_class __assertion = INITIALIZER;                 \
> > > +               kunit_failed_assertion(test,                                   \
> > > +                                      &__assertion.assert,                    \
> > > +                                      fmt,                                    \
> > > +                                      ##__VA_ARGS__);                         \
> > > +       }                                                                      \
> > >  } while (0)
> > >
> > >
> > > diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> > > index c7ed4aabec04..5ad671745483 100644
> > > --- a/lib/kunit/test.c
> > > +++ b/lib/kunit/test.c
> > > @@ -275,16 +275,11 @@ static void __noreturn kunit_abort(struct kunit *test)
> > >         WARN_ONCE(true, "Throw could not abort from test!\n");
> > >  }
> > >
> > > -void kunit_do_assertion(struct kunit *test,
> > > -                       struct kunit_assert *assert,
> > > -                       bool pass,
> > > -                       const char *fmt, ...)
> > > +void kunit_failed_assertion(struct kunit *test,
> > > +                           struct kunit_assert *assert,
> > > +                           const char *fmt, ...)
> > >  {
> > >         va_list args;
> > > -
> > > -       if (pass)
> > > -               return;
> > > -
> > >         va_start(args, fmt);
> > >
> > >         assert->message.fmt = fmt;
> > > @@ -297,7 +292,7 @@ void kunit_do_assertion(struct kunit *test,
> > >         if (assert->type == KUNIT_ASSERTION)
> > >                 kunit_abort(test);
> > >  }
> > > -EXPORT_SYMBOL_GPL(kunit_do_assertion);
> > > +EXPORT_SYMBOL_GPL(kunit_failed_assertion);
> > >
> > >  void kunit_init_test(struct kunit *test, const char *name, char *log)
> > >  {
> > > --
> > > 2.34.1.575.g55b058a8bb-goog
> > >