linux-kernel - Re: [PATCH v5 1/3] printf: convert self-test to KUnit

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Message-ID: <CAJ-ks9k5wLpeg7JFL-T6SYN62y7FWeQDbS9Q34TC-zY-dyM3HQ@mail.gmail.com>
Date: Fri, 7 Mar 2025 11:27:44 -0500
From: Tamir Duberstein <tamird@...il.com>
To: Petr Mladek <pmladek@...e.com>
Cc: Arpitha Raghunandan <98.arpi@...il.com>, David Gow <davidgow@...gle.com>, 
	Steven Rostedt <rostedt@...dmis.org>, Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
	Rasmus Villemoes <linux@...musvillemoes.dk>, Sergey Senozhatsky <senozhatsky@...omium.org>, 
	Andrew Morton <akpm@...ux-foundation.org>, Shuah Khan <shuah@...nel.org>, 
	Jonathan Corbet <corbet@....net>, Geert Uytterhoeven <geert@...ux-m68k.org>, 
	Madhavan Srinivasan <maddy@...ux.ibm.com>, Michael Ellerman <mpe@...erman.id.au>, 
	Nicholas Piggin <npiggin@...il.com>, Christophe Leroy <christophe.leroy@...roup.eu>, 
	Naveen N Rao <naveen@...nel.org>, Brendan Higgins <brendan.higgins@...ux.dev>, 
	linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org, 
	linux-doc@...r.kernel.org, linux-m68k@...ts.linux-m68k.org, 
	linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH v5 1/3] printf: convert self-test to KUnit

On Fri, Mar 7, 2025 at 11:01 AM Petr Mladek <pmladek@...e.com> wrote:
>
> On Thu 2025-03-06 09:25:43, Tamir Duberstein wrote:
> > On Thu, Mar 6, 2025 at 7:25 AM Petr Mladek <pmladek@...e.com> wrote:
> > >
> > > On Fri 2025-02-21 15:34:30, Tamir Duberstein wrote:
> > > > Convert the printf() self-test to a KUnit test.
> > > >
> > > > In the interest of keeping the patch reasonably-sized this doesn't
> > > > refactor the tests into proper parameterized tests - it's all one big
> > > > test case.
> > > >
> > > > --- a/lib/test_printf.c
> > > > +++ b/lib/tests/printf_kunit.c
> > > > @@ -57,52 +58,50 @@ do_test(int bufsize, const char *expect, int elen,
> > > >       va_end(aq);
> > > >
> > > >       if (ret != elen) {
> > > > -             pr_warn("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d\n",
> > > > +             tc_fail("vsnprintf(buf, %d, \"%s\", ...) returned %d, expected %d",
> > >
> > > 1. It looks a bit strange that the 1st patch replaces pr_warn() with
> > >    tc_fail() which hides KUNIT_FAIL().
> > >
> > >    And the 2nd patch replaces tc_fail() with KUNIT_FAIL().
> > >
> > >    It looks like a non-necessary churn.
> > >
> > >    It would be better to avoid the temporary "tc_fail" and swith to
> > >    KUNIT_FAIL() already in this patch.
> > >
> > >    I did not find any comment about this in the earier versions of the
> > >    patchset.
> > >
> > >    Is it just a result of the evolution of the patchset or
> > >    is there any motivation for this?
> >
> > The motivation was to keep the width of the macro the same in this
> > first patch for ease of review, particularly in the 7 instances where
> > the invocation wraps to a second line. If you prefer I go straight to
> > KUNIT_FAIL, I can make that change.
>
> I see. It might have been useful when the patch removed the trailing '\n'.
> But you are going to add it back. So there won't be any hidden change.
> So I would prefer to go straight to KUNIT_FAIL().

👍 I've restored all the newlines and added a few previously missing ones.

> > > > @@ -842,13 +836,15 @@ test_pointer(void)
> > > >       fourcc_pointer();
> > > >  }
> > > >
> > > > -static void __init selftest(void)
> > > > +static void printf_test(struct kunit *test)
> > > >  {
> > > >       alloced_buffer = kmalloc(BUF_SIZE + 2*PAD_SIZE, GFP_KERNEL);
> > > >       if (!alloced_buffer)
> > > >               return;
> > >
> > > I would use here:
> > >
> > >         KUNIT_ASSERT_NOT_NULL(test, alloced_buffer);
> > >
> > > And move the same change for the other kmalloc() location from
> > > the 2nd patch.
> >
> > I didn't do that here because I was trying to keep this patch as small
> > as possible, and I wrote that in the commit message.
> >
> > As for using KUNIT_ASSERT_NOT_NULL here, that would have to change
> > back to an error return in the 2nd patch because this code moves into
> > `suite_init`, which is called with `struct kunit_suite` rather than
> > `struct kunit_test`, and KUnit assertion macros do not work with the
> > former (and for good reason, because failures in suite setup cannot be
> > attributed to a particular test case).
>
> I see. KUNIT_ASSERT_NOT_NULL() can't be used in the .suite_exit() callback.
>
> > So I'd prefer to leave this as is.
>
> I agree to leave this as is.

👍