On Thu, May 18, 2023 at 4:39 AM David Gow davidgow@google.com wrote:
Add some basic documentation for kunit_add_action() and related deferred action functions.
Hi David!
This looks good to me. Just two typos below. Thanks!
Reviewed-by: Rae Moar rmoar@google.com
Signed-off-by: David Gow davidgow@google.com
This patch is new in v2.
Documentation/dev-tools/kunit/usage.rst | 51 +++++++++++++++++++++++++ 1 file changed, 51 insertions(+)
diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index 46957d1cbcbb..c2f0ed648385 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -615,6 +615,57 @@ For example: KUNIT_ASSERT_STREQ(test, buffer, ""); }
+Registering Cleanup Actions +---------------------------
+If you need to perform some cleanup beyond simple use of ``kunit_kzalloc``, +you can register a cusom "deferred action", which is a cleanup function
Looks like a typo here: "custom"
+run when the test exits (whether cleanly, or via a failed assertion).
+Actions are simple functions with no return value, and a single ``void*`` +context argument, and forfil the same role as "cleanup" functions in Python
Another small typo here as Bagas noted.
+and Go tests, "defer" statements in languages which support them, and +(in some cases) destructors in RAII languages.
+These are very useful for unregistering things from global lists, closing +files or other resources, or freeing resources.
+For example:
+.. code-block:: C
static void cleanup_device(void *ctx){struct device *dev = (struct device *)ctx;device_unregister(dev);}void example_device_test(struct kunit *test){struct my_device dev;device_register(&dev);kunit_add_action(test, &cleanup_device, &dev);}+Note that, for functions like device_unregister which only accept a single +pointer-sized argument, it's possible to directly cast that function to +a ``kunit_action_t`` rather than writing a wrapper function, for example:
+.. code-block:: C
kunit_add_action(test, (kunit_action_t *)&device_unregister, &dev);+``kunit_add_action`` can fail if, for example, the system is out of memory. +You can use ``kunit_add_action_or_reset`` instead which runs the action +immediately if it cannot be deferred.
+If you need more control over when the cleanup function is called, you +can trigger it early using ``kunit_release_action``, or cancel it entirely +with ``kunit_remove_action``.
Testing Static Functions
-- 2.40.1.698.g37aff9b760-goog