[LTP] [RFC PATCH 1/2] tst_test: Add test multiplex function

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> The test multiplex function is intended for running the test function in
> a loop for a different settings. The indended purpose is to run tests
> for both libc wrapper and raw syscall as well as for different syscall
> variants.
> 
> The commit itself adds a test_multiplex() function into the tst_test
> structure, if set this function is called in a loop before each test
> iteration and is responsible for changing the test variant into next
> one. The iterations continue until the function returns zero.

Hi,

on first look this looks like a workaround, because we have locked
ourselves out of .test function for timer tests.

Is there some way we could allow .test again for times tests?
Something user could override, provided he then runs the library
function that iterates over all usec values.

(sorry for pseudo-code)
// test
void my_test(int n)
{
  select_func = n;
  test_timer_test();
}

// library
void test_timer_test()
{
  for (i = 0; i < ARRAY_SIZE(tcases); i++)
    timer_test_fn(i);
}

Regards,
Jan

> 
> Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
> CC: Mark Salyzyn <salyzyn@android.com>
> CC: Steve Muckle <smuckle@google.com>
> CC: Jan Stancek <jstancek@redhat.com>
> ---
>  include/tst_test.h | 14 ++++++++++++++
>  lib/tst_test.c     | 11 +++++++++--
>  2 files changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/include/tst_test.h b/include/tst_test.h
> index da41f776d..b747b24d5 100644
> --- a/include/tst_test.h
> +++ b/include/tst_test.h
> @@ -146,6 +146,20 @@ struct tst_test {
>  	 */
>  	int all_filesystems:1;
>  
> +	/*
> +	 * If set this function is used to mutiplex between different test
> +	 * variants.
> +	 *
> +	 * Multiplexers are the way how to run the same test for different
> +	 * settings. The intended use is to test different syscall
> +	 * wrappers/variants but the API is generic and does not limit the
> +	 * usage in any way.
> +	 *
> +	 * Each time the function is called it switches to next test variant,
> +	 * returns zero if all variants has been iterated over.
> +	 */
> +	int (*test_multiplex)(void);
> +
>  	/* Minimal device size in megabytes */
>  	unsigned int dev_min_size;
>  
> diff --git a/lib/tst_test.c b/lib/tst_test.c
> index 7dd890b8d..6b033c879 100644
> --- a/lib/tst_test.c
> +++ b/lib/tst_test.c
> @@ -1009,8 +1009,15 @@ static void testrun(void)
>  		if (!cont)
>  			break;
>  
> -		run_tests();
> -		heartbeat();
> +		if (tst_test->test_multiplex) {
> +			while (tst_test->test_multiplex()) {
> +				run_tests();
> +				heartbeat();
> +			}
> +		} else {
> +			run_tests();
> +			heartbeat();
> +		}
>  	}
>  
>  	do_test_cleanup();
> --
> 2.19.2
> 
>