From: Marie Zhussupova marievic@google.com
Introduce example_params_test_with_init_dynamic_arr(). This new KUnit test demonstrates directly assigning a dynamic parameter array, using the kunit_register_params_array() macro, to a parameterized test context.
It highlights the use of param_init() and param_exit() for initialization and exit of a parameterized test, and their registration to the test case with KUNIT_CASE_PARAM_WITH_INIT().
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 --- Changes in v4: v3: https://lore.kernel.org/linux-kselftest/20250815103604.3857930-7-marievic@go... - No changes.
Changes in v3: v2: https://lore.kernel.org/all/20250811221739.2694336-7-marievic@google.com/ - No changes.
Changes in v2: v1: https://lore.kernel.org/all/20250729193647.3410634-9-marievic@google.com/ - kunit_array_gen_params() is now explicitly passed to KUNIT_CASE_PARAM_WITH_INIT() to be consistent with the parameterized test being defined by the existence of the generate_params() function. - param_init() was changed to output a log at the start of a parameterized test. - The parameter array was changed to be allocated using kunit_kmalloc_array(), a KUnit memory allocation API, as that would be the preferred/easier method. To still demonstrate a use of param_exit(), it now outputs a log at the end of the parameterized test. - 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 | 104 +++++++++++++++++++++++++++++++++ 1 file changed, 104 insertions(+)
diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c index 3e858367be01..9452b163956f 100644 --- a/lib/kunit/kunit-example-test.c +++ b/lib/kunit/kunit-example-test.c @@ -388,6 +388,107 @@ static void example_params_test_with_init(struct kunit *test) kunit_put_resource(res); }
+/* + * Helper function to create a parameter array of Fibonacci numbers. This example + * highlights a parameter generation scenario that is: + * 1. Not feasible to fully pre-generate at compile time. + * 2. Challenging to implement with a standard generate_params() function, + * as it only provides the previous parameter, while Fibonacci requires + * access to two preceding values for calculation. + */ +static void *make_fibonacci_params(struct kunit *test, size_t seq_size) +{ + int *seq; + + if (seq_size <= 0) + return NULL; + /* + * Using kunit_kmalloc_array here ties the lifetime of the array to + * the parameterized test i.e. it will get automatically cleaned up + * by KUnit after the parameterized test finishes. + */ + seq = kunit_kmalloc_array(test, seq_size, sizeof(int), GFP_KERNEL); + + if (!seq) + return NULL; + if (seq_size >= 1) + seq[0] = 0; + if (seq_size >= 2) + seq[1] = 1; + for (int i = 2; i < seq_size; i++) + seq[i] = seq[i - 1] + seq[i - 2]; + return seq; +} + +/* + * This is an example of a function that provides a description for each of the + * parameters. + */ +static void example_param_dynamic_arr_get_desc(struct kunit *test, const void *p, char *desc) +{ + const int *fib_num = p; + + snprintf(desc, KUNIT_PARAM_DESC_SIZE, "fibonacci param: %d", *fib_num); +} + +/* + * Example of a parameterized test param_init() function that registers a dynamic + * array of parameters. + */ +static int example_param_init_dynamic_arr(struct kunit *test) +{ + size_t seq_size; + int *fibonacci_params; + + kunit_info(test, "initializing parameterized test\n"); + + seq_size = 6; + fibonacci_params = make_fibonacci_params(test, seq_size); + + if (!fibonacci_params) + return -ENOMEM; + + /* + * Passes the dynamic parameter array information to the parameterized test + * context struct kunit. The array and its metadata will be stored in + * test->parent->params_array. The array itself will be located in + * params_data.params. + * + * Note that you will need to pass 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, fibonacci_params, seq_size, + example_param_dynamic_arr_get_desc); + return 0; +} + +/* + * Example of a parameterized test param_exit() function that outputs a log + * at the end of the parameterized test. It could also be used for any other + * teardown logic. + */ +static void example_param_exit_dynamic_arr(struct kunit *test) +{ + kunit_info(test, "exiting parameterized test\n"); +} + +/* + * Example of test that uses the registered dynamic array to perform assertions + * and expectations. + */ +static void example_params_test_with_init_dynamic_arr(struct kunit *test) +{ + const int *param = test->param_value; + int param_val; + + /* By design, param pointer will not be NULL. */ + KUNIT_ASSERT_NOT_NULL(test, param); + + param_val = *param; + KUNIT_EXPECT_EQ(test, param_val - param_val, 0); +} + /* * Here we make a list of all the test cases we want to add to the test suite * below. @@ -409,6 +510,9 @@ static struct kunit_case example_test_cases[] = { 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_PARAM_WITH_INIT(example_params_test_with_init_dynamic_arr, + kunit_array_gen_params, example_param_init_dynamic_arr, + example_param_exit_dynamic_arr), KUNIT_CASE_SLOW(example_slow_test), {} };