Re: [PATCH v2] Documentation: KUnit: Update filename best practices

[John Hubbard <jhubbard@nvidia.com>]

On 7/20/24 9:54 AM, Kees Cook wrote:
> Based on feedback from Linus[1] and follow-up discussions, change the
> suggested file naming for KUnit tests.
> 
> Link: https://lore.kernel.org/lkml/CAHk-=wgim6pNiGTBMhP8Kd3tsB7_JTAuvNJ=XYd3wPvvk=OHog@mail.gmail.com/ [1]
> Signed-off-by: Kees Cook <kees@kernel.org>
> ---
> Cc: David Gow <davidgow@google.com>
> Cc: Brendan Higgins <brendan.higgins@linux.dev>
> Cc: Rae Moar <rmoar@google.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Jonathan Corbet <corbet@lwn.net>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: linux-kselftest@vger.kernel.org
> Cc: kunit-dev@googlegroups.com
> Cc: linux-doc@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: linux-hardening@vger.kernel.org
> ---
>   Documentation/dev-tools/kunit/style.rst | 25 +++++++++++++++----------
>   1 file changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/Documentation/dev-tools/kunit/style.rst b/Documentation/dev-tools/kunit/style.rst
> index b6d0d7359f00..1538835cd0e2 100644
> --- a/Documentation/dev-tools/kunit/style.rst
> +++ b/Documentation/dev-tools/kunit/style.rst
> @@ -188,15 +188,20 @@ For example, a Kconfig entry might look like:
>   Test File and Module Names
>   ==========================
>   
> -KUnit tests can often be compiled as a module. These modules should be named
> -after the test suite, followed by ``_test``. If this is likely to conflict with
> -non-KUnit tests, the suffix ``_kunit`` can also be used.
> -
> -The easiest way of achieving this is to name the file containing the test suite
> -``<suite>_test.c`` (or, as above, ``<suite>_kunit.c``). This file should be
> -placed next to the code under test.
> +Whether a KUnit test is compiled as a separate module or via an
> +``#include`` in a core kernel source file, the file should be named
> +after the test suite, followed by ``_kunit``, and live in a ``tests``
> +subdirectory to avoid conflicting with regular modules (e.g. if "foobar"
> +is the core module, then "foobar_kunit" is the KUnit test module) or the
> +core kernel source file names (e.g. for tab-completion). Many existing
> +tests use a ``_test`` suffix, but this is considered deprecated.

For this paragraph, may I suggest this wording below? It attempts to
explain the _kunit a bit (without leaving anything behind that would need
to be changed later, if/when people rename things from _test.c to _kunit.c),
as well as fixing up the sentence structure slightly:


Whether a KUnit test is compiled as a separate module or via an
``#include`` in a core kernel source file, the file should be named
after the test suite, followed by ``_kunit``, and live in a ``tests``
subdirectory. This is to avoid conflicting with regular modules (e.g. if
"foobar" is the core module, then "foobar_kunit" is the KUnit test
module) or with the core kernel source file names (e.g. for
tab-completion). The ``_kunit`` suffix was chosen over the older (and
now deprecated) ``_test`` suffix, because KUnit behavior is sufficiently
distinct that it is worth identifying at file name level.


> +
> +So for the common case, name the file containing the test suite
> +``tests/<suite>_kunit.c``. The ``tests`` directory should be placed at
> +the same level as the code under test. For example, tests for
> +``lib/string.c`` live in ``lib/tests/string_kunit.c``.
>   
>   If the suite name contains some or all of the name of the test's parent
> -directory, it may make sense to modify the source filename to reduce redundancy.
> -For example, a ``foo_firmware`` suite could be in the ``foo/firmware_test.c``
> -file.
> +directory, it may make sense to modify the source filename to reduce
> +redundancy. For example, a ``foo_firmware`` suite could be in the
> +``tests/foo/firmware_kunit.c`` file.

Whether you use that wording or not, this looks good, so:

Reviewed-by: John Hubbard <jhubbard@nvidia.com>

thanks,
-- 
John Hubbard
NVIDIA