Re: [PATCH] Documentation: kunit: Add naming guidelines

[Marco Elver]

On Thu, Jul 02, 2020 at 12:14AM -0700, David Gow wrote:
> As discussed in [1], KUnit tests have hitherto not had a particularly
> consistent naming scheme. This adds documentation outlining how tests
> and test suites should be named, including how those names should be
> used in Kconfig entries and filenames.
> 
> [1]:
> https://lore.kernel.org/linux-kselftest/202006141005.BA19A9D3@keescook/t/#u
> 
> Signed-off-by: David Gow <davidgow@xxxxxxxxxx>
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> ---
...
> +An example Kconfig entry:
> +
> +.. code-block:: none
> +
> +        config FOO_KUNIT_TEST
> +                tristate "KUnit test for foo" if !KUNIT_ALL_TESTS
> +                depends on KUNIT
> +                default KUNIT_ALL_TESTS
> +                help
> +                    This builds unit tests for foo.
> +
> +                    For more information on KUnit and unit tests in general, please refer
> +                    to the KUnit documentation in Documentation/dev-tools/kunit
> +
> +                    If unsure, say N
> +
> +
> +Test Filenames
> +==============
> +
> +Where possible, test suites should be placed in a separate source file in the
> +same directory as the code being tested.
> +
> +This file should be named ``<suite>_kunit.c``. It may make sense to strip
> +excessive namespacing from the source filename (e.g., ``firmware_kunit.c`` instead of
> +``<drivername>_firmware.c``), but please ensure the module name does contain the
> +full suite name.

First of all, thanks for the talk yesterday! I only looked at this
because somebody pasted the LKML link. :-)

The example about excessive namespacing seems confusing. Was it supposed
to be 

	[...] firmware_kunit.c`` instead of ``<drivername>_firmware_kunit.c [...]

?


While I guess this ship has sailed, and *_kunit.c is the naming
convention now, I hope this is still just a recommendation and names of
the form *-test.c are not banned!

$> git grep 'KUNIT.*-test.o'
	drivers/base/power/Makefile:obj-$(CONFIG_PM_QOS_KUNIT_TEST) += qos-test.o
	drivers/base/test/Makefile:obj-$(CONFIG_KUNIT_DRIVER_PE_TEST) += property-entry-test.o
	fs/ext4/Makefile:obj-$(CONFIG_EXT4_KUNIT_TESTS)		+= ext4-inode-test.o
	kernel/Makefile:obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o
	lib/Makefile:obj-$(CONFIG_LIST_KUNIT_TEST) += list-test.o
	lib/kunit/Makefile:obj-$(CONFIG_KUNIT_TEST) +=		kunit-test.o
	lib/kunit/Makefile:obj-$(CONFIG_KUNIT_TEST) +=		string-stream-test.o
	lib/kunit/Makefile:obj-$(CONFIG_KUNIT_EXAMPLE_TEST) +=	kunit-example-test.o

$> git grep 'KUNIT.*_kunit.o'
# Returns nothing


Just an idea: Maybe the names are also an opportunity to distinguish
real _unit_ style tests and then the rarer integration-style tests. I
personally prefer using the more generic *-test.c, at least for the
integration-style tests I've been working on (KUnit is still incredibly
valuable for integration-style tests, because otherwise I'd have to roll
my own poor-man's version of KUnit, so thank you!). Using *_kunit.c for
such tests is unintuitive, because the word "unit" hints at "unit tests"
-- and having descriptive (and not misleading) filenames is still
important. So I hope you won't mind if *-test.c are still used where
appropriate.

Thanks,
-- Marco