Re: [PATCH v8] fat: Add KUnit tests for checksums and timestamps

[David Gow]

On Wed, May 5, 2021 at 2:36 AM 'Brendan Higgins' via KUnit Development
<kunit-dev@xxxxxxxxxxxxxxxx> wrote:
>
> On Thu, Apr 15, 2021 at 11:56:23PM -0700, David Gow wrote:
> > Add some basic sanity-check tests for the fat_checksum() function and
> > the fat_time_unix2fat() and fat_time_fat2unix() functions. These unit
> > tests verify these functions return correct output for a number of test
> > inputs.
> >
> > These tests were inspored by -- and serve a similar purpose to -- the
>                    ^^^^^^^^
>         I am guessing this is supposed to be "inspired".
>

Oops -- yup. This is a typo. I can resend a version with this fixed if
you think that makes sense, otherwise I'll just hold it over in case I
need to send out a new version.

> > timestamp parsing KUnit tests in ext4[1].
> >
> > Note that, unlike fat_time_unix2fat, fat_time_fat2unix wasn't previously
> > exported, so this patch exports it as well. This is required for the
> > case where we're building the fat and fat_test as modules.
> >
> > [1]:
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/fs/ext4/inode-test.c
> >
> > Signed-off-by: David Gow <davidgow@xxxxxxxxxx>
> > Acked-by: OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>
>
> Aside from the nit above, and the *potential* nit and question below.
> Everything here looks good to me.
>
> Reviewed-by: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
>
> > ---
> >
> > It's been a while, but this hopefully is a final version of the FAT KUnit
> > patchset. It has a number of changes to keep it up-to-date with current
> > KUnit standards, notably the use of parameterised tests and the addition
> > of a '.kunitconfig' file to allow for easy testing. It also fixes an
> > endianness tagging issue picked up by the kernel test robot under sparse
> > on pa-risc.
> >
> > Cheers,
> > -- David
>
> [...]
>
> > diff --git a/fs/fat/fat_test.c b/fs/fat/fat_test.c
> > new file mode 100644
> > index 000000000000..febd25f57d4b
> > --- /dev/null
> > +++ b/fs/fat/fat_test.c
> > @@ -0,0 +1,197 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * KUnit tests for FAT filesystems.
> > + *
> > + * Copyright (C) 2020 Google LLC.
>
> Nit: I know you wrote this last year, but I have had other maintainers
> tell me the Copyright date should be set to when the final version of
> the patch is sent out.
>
> I personally don't care, and I don't think you should resend this patch
> just for that, but figured I would mention.
>

Hmm... I've definitely heard this both ways, but I can easily update
the year if I need to send a new version out.

> > + * Author: David Gow <davidgow@xxxxxxxxxx>
> > + */
> > +
> > +#include <kunit/test.h>
> > +
> > +#include "fat.h"
> > +
> > +static void fat_checksum_test(struct kunit *test)
> > +{
> > +     /* With no extension. */
> > +     KUNIT_EXPECT_EQ(test, fat_checksum("VMLINUX    "), (u8)44);
> > +     /* With 3-letter extension. */
> > +     KUNIT_EXPECT_EQ(test, fat_checksum("README  TXT"), (u8)115);
> > +     /* With short (1-letter) extension. */
> > +     KUNIT_EXPECT_EQ(test, fat_checksum("ABCDEFGHA  "), (u8)98);
>
> How do you get the magic values? Or is this just supposed to be a
> regression test?

This is mainly meant to be a regression test, and the values did
originally come from just running fat_checksum. I have, however,
checked that Windows 98 produces the same values (on a FAT12
filesystem).

> Not going to pretend I understand FAT, but everything else in this test
> makes sense from a logical/testing/readability point of view.
>
> Cheers!
>
> [...]
>
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