common KUnit Kconfig and file naming (was: Re: [PATCH] lib: kunit_test_overflow: add KUnit test of check_*_overflow functions)

[Kees Cook <keescook@chromium.org>]

On Sat, Jun 13, 2020 at 02:51:17PM +0800, David Gow wrote:
> Yeah, _KUNIT_TEST was what we've sort-of implicitly decided on for
> config names, but the documentation does need to happen.

That works for me. It still feels redundant, but all I really want is a
standard name. :)

> We haven't put as much thought into standardising the filenames much, though.

I actually find this to be much more important because it is more
end-user-facing (i.e. in module naming, in build logs, in scripts, on
filesystem, etc -- CONFIG is basically only present during kernel build).
Trying to do any sorting or greping really needs a way to find all the
kunit pieces.

> Both of these are slightly complicated by cases like this where tests
> are being ported from a non-KUnit test to KUnit. There's a small
> argument there for trying to keep the name the same, though personally
> I suspect consistency is more important.

Understood. I think consistency is preferred too, especially since the
driving reason to make this conversions is to gain consistency with the
actual tests themselves.

> Alas, the plans to document test coding style / conventions kept
> getting pre-empted: I'll drag it back up to the top of the to-do list,
> and see if we can't prioritise it. I think we'd hoped to be able to
> catch these in review, but between a bit of forgetfulness and a few
> tests going upstream without our seeing them has made it obvious that
> doesn't work.
> 
> Once something's documented (and the suitable bikeshedding has
> subsided), we can consider renaming existing tests if that seems
> worthwhile.

Yes please! :)

> My feeling is we'll go for:
> - Kconfig name: ~_KUNIT_TEST

As mentioned, I'm fine with this, but prefer ~_KUNIT

> - filename: ~-test.c

I really don't like this. Several reasons reasons:

- it does not distinguish it from other tests -- there is no way to
  identify kunit tests from non-kunit tests from directory listings,
  build log greps, etc.

- the current "common" naming has been with a leading "test", ignoring
  kunit, tools/, and samples/:

	53 test_*.c
	27 *_test.c
	19 *[a-z0-9]test.c
	19 selftest*.c
	16 test-*.c
	11 *-test.c
	11 test[a-z0-9]*.c
	 8 *-tests.c
	 5 *-selftest.c
	 4 *_test_*.c
	 1 *_selftest_*.c
	 1 *_selftests.c

(these counts might be a bit off -- my eyes started to cross while
constructing regexes)

- dashes are converted to _ in module names, leading to some confusion
  between .c file and .ko file.

I'd strongly prefer ~_kunit.c, but could live with _kunit_test.c (even
though it's redundant).

> At least for the initial draft documentation, as those seem to be most
> common, but I think a thread on that would probably be the best place
> to add it.

I'm ready! :) (Subject updated)

> This would also be a good opportunity to document the "standard" KUnit
> boilerplate help text in the Kconfig options.

Ah yeah, good idea.

-- 
Kees Cook