[PATCH 0/4] kunit: Add helpers for creating test-managed devices

[davidgow]

KUnit tests often need to provide a struct device, and thus far have
mostly been using root_device_register() or platform devices to create
a 'fake device' for use with, e.g., code which uses device-managed
resources. This has several disadvantages, including not being designed
for test use, scattering files in sysfs, and requiring manual teardown
on test exit, which may not always be possible in case of failure.

Instead, introduce a set of helper functions which allow devices
(internally a struct kunit_device) to be created and managed by KUnit --
i.e., they will be automatically unregistered on test exit. These
helpers can either use a user-provided struct device_driver, or have one
automatically created and managed by KUnit. In both cases, the device
lives on a new kunit_bus.

This is a follow-up to a previous proposal here:
https://lore.kernel.org/linux-kselftest/20230325043104.3761770-1-davidgow@xxxxxxxxxx/

(The kunit_defer() function in the first patch there has since been
merged as the 'deferred actions' feature.)

My intention is to take this whole series in via the kselftest/kunit
branch, but I'm equally okay with splitting up the later patches which
use this to go via the various subsystem trees in case there are merge
conflicts.

Cheers,
-- David

Signed-off-by: David Gow <davidgow@xxxxxxxxxx>
---
David Gow (4):
      kunit: Add APIs for managing devices
      fortify: test: Use kunit_device
      overflow: Replace fake root_device with kunit_device
      ASoC: topology: Replace fake root_device with kunit_device in tests

 Documentation/dev-tools/kunit/usage.rst |  49 +++++++++
 include/kunit/device.h                  |  76 ++++++++++++++
 lib/fortify_kunit.c                     |   5 +-
 lib/kunit/Makefile                      |   3 +-
 lib/kunit/device.c                      | 176 ++++++++++++++++++++++++++++++++
 lib/kunit/kunit-test.c                  |  68 +++++++++++-
 lib/kunit/test.c                        |   3 +
 lib/overflow_kunit.c                    |   5 +-
 sound/soc/soc-topology-test.c           |  11 +-
 9 files changed, 382 insertions(+), 14 deletions(-)
---
base-commit: c8613be119892ccceffbc550b9b9d7d68b995c9e
change-id: 20230718-kunit_bus-ab19c4ef48dc

Best regards,
-- 
David Gow <davidgow@xxxxxxxxxx>