On Tue, 12 Aug 2025 at 06:18, Marie Zhussupova <marie...@google.com> wrote: > > Add example_params_test_with_init() to illustrate how to manage > shared resources across a parameterized KUnit test. This example > showcases the use of the new param_init() function and its registration > to a test using the KUNIT_CASE_PARAM_WITH_INIT() macro. > > Additionally, the test demonstrates how to directly pass a parameter array > to the parameterized test context via kunit_register_params_array() > and leveraging the Resource API for shared resource management. > > Signed-off-by: Marie Zhussupova <marie...@google.com> > ---
This looks fine to me. One note below about one of the comments.
Otherwise,
Reviewed-by: David Gow <david...@google.com>
Cheers,
-- David
>
> Changes in v2:
>
> - kunit_array_gen_params() is now explicitly passed to
> KUNIT_CASE_PARAM_WITH_INIT() to be consistent with
> a parameterized test being defined by the existence
> of the generate_params() function.
> - The comments were edited to be more concise.
> - The patch header was changed to reflect that this example
> test's intent is more aligned with showcasing using the
> Resource API for shared resource management.
> - The comments and the commit message were changed to
> reflect the parameterized testing terminology. See
> the patch series cover letter change log for the
> definitions.
>
> ---
>
> lib/kunit/kunit-example-test.c | 118 +++++++++++++++++++++++++++++++++
> 1 file changed, 118 insertions(+)
>
> diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c
> index 3056d6bc705d..f2819ee58965 100644
> --- a/lib/kunit/kunit-example-test.c
> +++ b/lib/kunit/kunit-example-test.c
> @@ -277,6 +277,122 @@ static void example_slow_test(struct kunit *test)
> KUNIT_EXPECT_EQ(test, 1 + 1, 2);
> }
>
> +/*
> + * This custom function allocates memory and sets the information we want
> + * stored in the kunit_resource->data field.
> + */
> +static int example_resource_init(struct kunit_resource *res, void *context)
> +{
> + int *info = kmalloc(sizeof(*info), GFP_KERNEL);
> +
> + if (!info)
> + return -ENOMEM;
> + *info = *(int *)context;
> + res->data = info;
> + return 0;
> +}
> +
> +/*
> + * This function deallocates memory for the kunit_resource->data field.
> + */
> +static void example_resource_free(struct kunit_resource *res)
> +{
> + kfree(res->data);
> +}
> +
> +/*
> + * This match function is invoked by kunit_find_resource() to locate
> + * a test resource based on certain criteria.
> + */
> +static bool example_resource_alloc_match(struct kunit *test,
> + struct kunit_resource *res,
> + void *match_data)
> +{
> + return res->data && res->free == example_resource_free;
> +}
> +
> +/*
> + * This is an example of a function that provides a description for each of
> the
> + * parameters in a parameterized test.
> + */
> +static void example_param_array_get_desc(struct kunit *test, const void *p,
> char *desc)
> +{
> + const struct example_param *param = p;
> +
> + snprintf(desc, KUNIT_PARAM_DESC_SIZE,
> + "example check if %d is less than or equal to 3",
> param->value);
> +}
> +
> +/*
> + * This function gets passed in the parameterized test context i.e. the
> + * struct kunit belonging to the parameterized test. You can use this
> function
> + * to add resources you want shared across the whole parameterized test or
> + * for additional setup.
> + */
> +static int example_param_init(struct kunit *test)
> +{
> + int ctx = 3; /* Data to be stored. */
> + size_t arr_size = ARRAY_SIZE(example_params_array);
> +
> + /*
> + * This allocates a struct kunit_resource, sets its data field to
> + * ctx, and adds it to the struct kunit's resources list. Note that
> + * this is parameterized test managed. So, it doesn't need to have
> + * a custom exit function to deallocation as it will get cleaned up at
> + * the end of the parameterized test.
> + */
> + void *data = kunit_alloc_resource(test, example_resource_init,
> example_resource_free,
> + GFP_KERNEL, &ctx);
> +
> + if (!data)
> + return -ENOMEM;
> + /*
> + * Pass the parameter array information to the parameterized test
> context
> + * struct kunit. Note that you will need to provide
> kunit_array_gen_params()
> + * as the generator function to KUNIT_CASE_PARAM_WITH_INIT() when
> registering
> + * a parameter array this route.
> + *
> + * Alternatively, since this is a static array we can also use
> + * KUNIT_CASE_PARAM_ARRAY(,DESC) to create a `*_gen_params()`
> function
> + * and pass that to KUNIT_CASE_PARAM_WITH_INIT() instead of
> registering
> + * the parameter array here.
Maybe we should note that KUNIT_CASE_PARAM_ARRAY{,_DESC}() doesn't let
us set an init function, so would be less useful here.
> + */
> + kunit_register_params_array(test, example_params_array, arr_size,
> + example_param_array_get_desc);
> + return 0;
> +}
> +
> +/*
> + * This is an example of a test that uses shared resources available in the
> + * parameterized test context.
> + */
> +static void example_params_test_with_init(struct kunit *test)
> +{
> + int threshold;
> + struct kunit_resource *res;
> + const struct example_param *param = test->param_value;
> +
> + /* By design, param pointer will not be NULL. */
> + KUNIT_ASSERT_NOT_NULL(test, param);
> +
> + /*
> + * Here we pass test->parent to search for shared resources in the
> + * parameterized test context.
> + */
> + res = kunit_find_resource(test->parent, example_resource_alloc_match,
> NULL);
> +
> + KUNIT_ASSERT_NOT_NULL(test, res);
> +
> + /* Since kunit_resource->data is a void pointer we need to typecast
> it. */
> + threshold = *((int *)res->data);
> +
> + /* Assert that the parameter is less than or equal to a certain
> threshold. */
> + KUNIT_ASSERT_LE(test, param->value, threshold);
> +
> + /* This decreases the reference count after calling
> kunit_find_resource(). */
> + kunit_put_resource(res);
> +}
> +
> /*
> * Here we make a list of all the test cases we want to add to the test suite
> * below.
> @@ -296,6 +412,8 @@ static struct kunit_case example_test_cases[] = {
> KUNIT_CASE(example_static_stub_using_fn_ptr_test),
> KUNIT_CASE(example_priv_test),
> KUNIT_CASE_PARAM(example_params_test, example_gen_params),
> + KUNIT_CASE_PARAM_WITH_INIT(example_params_test_with_init,
> kunit_array_gen_params,
> + example_param_init, NULL),
> KUNIT_CASE_SLOW(example_slow_test),
> {}
> };
> --
> 2.51.0.rc0.205.g4a044479a3-goog
>
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