kunit: Introduce param_init/exit for parameterized test context management

Add (*param_init) and (*param_exit) function pointers to
`struct kunit_case`. Users will be able to set them via the new
KUNIT_CASE_PARAM_WITH_INIT() macro.

param_init/exit will be invoked by kunit_run_tests() once before and once
after the parameterized test, respectively. They will receive the
`struct kunit` that holds the parameterized test context; facilitating
init and exit for shared state.

This patch also sets param_init/exit to None in rust/kernel/kunit.rs.

Link: https://lore.kernel.org/r/20250826091341.1427123-3-davidgow@google.com
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>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 9766403afd56..fc8fd55b2dfb 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -92,6 +92,8 @@ struct kunit_attributes {
  * @name:     the name of the test case.
  * @generate_params: the generator function for parameterized tests.
  * @attr:     the attributes associated with the test
+ * @param_init: The init function to run before a parameterized test.
+ * @param_exit: The exit function to run after a parameterized test.
  *
  * A test case is a function with the signature,
  * ``void (*)(struct kunit *)``
@@ -128,6 +130,8 @@ struct kunit_case {
 	const char *name;
 	const void* (*generate_params)(const void *prev, char *desc);
 	struct kunit_attributes attr;
+	int (*param_init)(struct kunit *test);
+	void (*param_exit)(struct kunit *test);
 
 	/* private: internal use only. */
 	enum kunit_status status;
@@ -219,6 +223,27 @@ static inline char *kunit_status_to_ok_not_ok(enum kunit_status status)
 		  .attr = attributes, .module_name = KBUILD_MODNAME}
 
 /**
+ * KUNIT_CASE_PARAM_WITH_INIT - Define a parameterized KUnit test case with custom
+ * param_init() and param_exit() functions.
+ * @test_name: The function implementing the test case.
+ * @gen_params: The function to generate parameters for the test case.
+ * @init: A reference to the param_init() function to run before a parameterized test.
+ * @exit: A reference to the param_exit() function to run after a parameterized test.
+ *
+ * Provides the option to register param_init() and param_exit() functions.
+ * param_init/exit will be passed the parameterized test context and run once
+ * before and once after the parameterized test. The init function can be used
+ * to add resources to share between parameter runs, and any other setup logic.
+ * The exit function can be used to clean up resources that were not managed by
+ * the parameterized test, and any other teardown logic.
+ */
+#define KUNIT_CASE_PARAM_WITH_INIT(test_name, gen_params, init, exit)		\
+		{ .run_case = test_name, .name = #test_name,			\
+		  .generate_params = gen_params,				\
+		  .param_init = init, .param_exit = exit,			\
+		  .module_name = KBUILD_MODNAME}
+
+/**
  * struct kunit_suite - describes a related collection of &struct kunit_case
  *
  * @name:	the name of the test. Purely informational.