From: Marie Zhussupova marievic@google.com
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.
Reviewed-by: Rae Moar rmoar@google.com Reviewed-by: David Gow davidgow@google.com Signed-off-by: Marie Zhussupova marievic@google.com Signed-off-by: David Gow davidgow@google.com ---
No changes in v4: v3: https://lore.kernel.org/linux-kselftest/20250815103604.3857930-6-marievic@go...
Changes in v3: v2: https://lore.kernel.org/all/20250811221739.2694336-6-marievic@google.com/ - Code comment edits.
Changes in v2: v1: https://lore.kernel.org/all/20250729193647.3410634-8-marievic@google.com/ - 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 | 113 +++++++++++++++++++++++++++++++++ 1 file changed, 113 insertions(+)
diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c index 3056d6bc705d..3e858367be01 100644 --- a/lib/kunit/kunit-example-test.c +++ b/lib/kunit/kunit-example-test.c @@ -277,6 +277,117 @@ 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. + */ + 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 +407,8 @@ 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), {} };