From 5fb1a8c671473c59ed556035346fa9f2b2b430f1 Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Thu, 21 Dec 2023 10:38:57 +0000 Subject: [PATCH] kunit: Add example of kunit_activate_static_stub() with pointer-to-function Adds a variant of example_static_stub_test() that shows use of a pointer-to-function with kunit_activate_static_stub(). A const pointer to the add_one() function is declared. This pointer-to-function is passed to kunit_activate_static_stub() and kunit_deactivate_static_stub() instead of passing add_one directly. Signed-off-by: Richard Fitzgerald Reviewed-by: David Gow Signed-off-by: Shuah Khan --- lib/kunit/kunit-example-test.c | 35 ++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c index 359dbee10201..798924f7cc86 100644 --- a/lib/kunit/kunit-example-test.c +++ b/lib/kunit/kunit-example-test.c @@ -168,6 +168,16 @@ static int subtract_one(int i) return i - 1; } +/* + * If the function to be replaced is static within a module it is + * useful to export a pointer to that function instead of having + * to change the static function to a non-static exported function. + * + * This pointer simulates a module exporting a pointer to a static + * function. + */ +static int (* const add_one_fn_ptr)(int i) = add_one; + /* * This test shows the use of static stubs. */ @@ -187,6 +197,30 @@ static void example_static_stub_test(struct kunit *test) KUNIT_EXPECT_EQ(test, add_one(1), 2); } +/* + * This test shows the use of static stubs when the function being + * replaced is provided as a pointer-to-function instead of the + * actual function. This is useful for providing access to static + * functions in a module by exporting a pointer to that function + * instead of having to change the static function to a non-static + * exported function. + */ +static void example_static_stub_using_fn_ptr_test(struct kunit *test) +{ + /* By default, function is not stubbed. */ + KUNIT_EXPECT_EQ(test, add_one(1), 2); + + /* Replace add_one() with subtract_one(). */ + kunit_activate_static_stub(test, add_one_fn_ptr, subtract_one); + + /* add_one() is now replaced. */ + KUNIT_EXPECT_EQ(test, add_one(1), 0); + + /* Return add_one() to normal. */ + kunit_deactivate_static_stub(test, add_one_fn_ptr); + KUNIT_EXPECT_EQ(test, add_one(1), 2); +} + static const struct example_param { int value; } example_params_array[] = { @@ -259,6 +293,7 @@ static struct kunit_case example_test_cases[] = { KUNIT_CASE(example_mark_skipped_test), KUNIT_CASE(example_all_expect_macros_test), KUNIT_CASE(example_static_stub_test), + 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_SLOW(example_slow_test),