[PATCH 3/9] kunit: Pass additional context to generate_params for parameterized testing

[Rae Moar]

On Tue, Jul 29, 2025 at 3:37 PM Marie Zhussupova <marievic at google.com> wrote:
>
> To enable more complex parameterized test scenarios,
> the `generate_params` function sometimes needs additional
> context beyond just the previously generated parameter.
> This patch modifies the `generate_params` function signature
> to include an extra `struct kunit *test` argument, giving
> users access to the parent kunit test's context when
> generating subsequent parameters.
>
> The `struct kunit *test` argument was added as the first parameter
> to the function signature as it aligns with the convention
> of other KUnit functions that accept `struct kunit *test` first.
> This also mirrors the "this" or "self" reference found
> in object-oriented programming languages.
>
> Signed-off-by: Marie Zhussupova <marievic at google.com>

Hello!

Extremely happy about this change. This will provide us much more
flexibility when defining test parameters. Thank you for this
implementation!

Reviewed-by: Rae Moar <rmoar at google.com>


-Rae

> ---
>  include/kunit/test.h | 9 ++++++---
>  lib/kunit/test.c     | 5 +++--
>  2 files changed, 9 insertions(+), 5 deletions(-)
>
> diff --git a/include/kunit/test.h b/include/kunit/test.h
> index d8dac7efd745..4ba65dc35710 100644
> --- a/include/kunit/test.h
> +++ b/include/kunit/test.h
> @@ -128,7 +128,8 @@ struct kunit_attributes {
>  struct kunit_case {
>         void (*run_case)(struct kunit *test);
>         const char *name;
> -       const void* (*generate_params)(const void *prev, char *desc);
> +       const void* (*generate_params)(struct kunit *test,
> +                                      const void *prev, char *desc);
>         struct kunit_attributes attr;
>
>         /*
> @@ -1701,7 +1702,8 @@ do {                                                                             \
>   * Define function @name_gen_params which uses @array to generate parameters.
>   */
>  #define KUNIT_ARRAY_PARAM(name, array, get_desc)                                               \
> -       static const void *name##_gen_params(const void *prev, char *desc)                      \
> +       static const void *name##_gen_params(struct kunit *test,                                \
> +                                            const void *prev, char *desc)                      \
>         {                                                                                       \
>                 typeof((array)[0]) *__next = prev ? ((typeof(__next)) prev) + 1 : (array);      \
>                 if (__next - (array) < ARRAY_SIZE((array))) {                                   \
> @@ -1722,7 +1724,8 @@ do {                                                                             \
>   * Define function @name_gen_params which uses @array to generate parameters.
>   */
>  #define KUNIT_ARRAY_PARAM_DESC(name, array, desc_member)                                       \
> -       static const void *name##_gen_params(const void *prev, char *desc)                      \
> +       static const void *name##_gen_params(struct kunit *test,                                \
> +                                            const void *prev, char *desc)                      \
>         {                                                                                       \
>                 typeof((array)[0]) *__next = prev ? ((typeof(__next)) prev) + 1 : (array);      \
>                 if (__next - (array) < ARRAY_SIZE((array))) {                                   \
> diff --git a/lib/kunit/test.c b/lib/kunit/test.c
> index d80b5990d85d..f50ef82179c4 100644
> --- a/lib/kunit/test.c
> +++ b/lib/kunit/test.c
> @@ -696,7 +696,7 @@ int kunit_run_tests(struct kunit_suite *suite)
>                         /* Get initial param. */
>                         param_desc[0] = '\0';
>                         /* TODO: Make generate_params try-catch */
> -                       curr_param = test_case->generate_params(NULL, param_desc);
> +                       curr_param = test_case->generate_params(&test, NULL, param_desc);
>                         test_case->status = KUNIT_SKIPPED;
>                         kunit_log(KERN_INFO, &test, KUNIT_SUBTEST_INDENT KUNIT_SUBTEST_INDENT
>                                   "KTAP version 1\n");
> @@ -727,7 +727,8 @@ int kunit_run_tests(struct kunit_suite *suite)
>
>                                 /* Get next param. */
>                                 param_desc[0] = '\0';
> -                               curr_param = test_case->generate_params(curr_param, param_desc);
> +                               curr_param = test_case->generate_params(&test, curr_param,
> +                                                                       param_desc);
>                         }
>                 }
>
> --
> 2.50.1.552.g942d659e1b-goog
>