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kunit: Add example of kunit_activate_static_stub() with pointer-to-function

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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 <rf@opensource.cirrus.com>
Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
This commit is contained in:
Richard Fitzgerald 2023-12-21 10:38:57 +00:00 committed by Shuah Khan
parent fcbac39b7d
commit 5fb1a8c671
1 changed files with 35 additions and 0 deletions
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35
lib/kunit/kunit-example-test.c
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@ -168,6 +168,16 @@ static int subtract_one(int i)
return i - 1; 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. * 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); 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 { static const struct example_param {
int value; int value;
} example_params_array[] = { } example_params_array[] = {
@ -259,6 +293,7 @@ static struct kunit_case example_test_cases[] = {
KUNIT_CASE(example_mark_skipped_test), KUNIT_CASE(example_mark_skipped_test),
KUNIT_CASE(example_all_expect_macros_test), KUNIT_CASE(example_all_expect_macros_test),
KUNIT_CASE(example_static_stub_test), KUNIT_CASE(example_static_stub_test),
KUNIT_CASE(example_static_stub_using_fn_ptr_test),
KUNIT_CASE(example_priv_test), KUNIT_CASE(example_priv_test),
KUNIT_CASE_PARAM(example_params_test, example_gen_params), KUNIT_CASE_PARAM(example_params_test, example_gen_params),
KUNIT_CASE_SLOW(example_slow_test), KUNIT_CASE_SLOW(example_slow_test),