Re: [kvm-unit-tests PATCH] x86: setjmp: check expected value of "i" to give better feedback

[Sean Christopherson <sean.j.christopherson@intel.com>]

On Tue, Sep 10, 2019 at 07:31:42PM -0700, Bill Wendling wrote:
> Use a list of expected values instead of printing out numbers, which
> aren't very meaningful. This prints only if the expected and actual
> values differ.
> 
> Signed-off-by: Bill Wendling <morbo@google.com>
> ---
>  x86/setjmp.c | 19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/x86/setjmp.c b/x86/setjmp.c
> index 976a632..c0b25ec 100644
> --- a/x86/setjmp.c
> +++ b/x86/setjmp.c
> @@ -1,19 +1,30 @@
>  #include "libcflat.h"
>  #include "setjmp.h"
>  
> +int expected[] = {

This should be 'static const'.

> +	0, 1, 2, 3, 4, 5, 6, 7, 8, 9
> +};
> +
> +#define NUM_EXPECTED (sizeof(expected) / sizeof(int))

How about NUM_LONGJMPS?  And you can use ARRAY_SIZE.

> +
>  int main(void)
>  {
> -    volatile int i;
> +    volatile int i = -1, index = 0;
> +    volatile bool had_errors = false;
>      jmp_buf j;
>  
>      if (setjmp(j) == 0) {
>  	    i = 0;
>      }
> -    printf("%d\n", i);
> -    if (++i < 10) {
> +    if (expected[index++] != i) {
> +	    printf("FAIL: actual %d / expected %d\n", i, expected[index]);

This will print the wrong expected value on failure since index was
incremented above.

> +            had_errors = true;
> +    }

had_errors seems like overkill.  If we fail once, what's the pointing of
continuing on? 

> +    if (index < NUM_EXPECTED) {
> +	    i++;
>  	    longjmp(j, 1);
>      }

And we should pass i to longjmp(), otherwise there isn't really any point
to having separate index and i variables, e.g.:

	volatile int index = 0;
	jmp_buf j;
	int i;

	i = setjmp(j);

	if (expected[index] != i) {
		printf("FAIL: actual %d / expected %d\n", i, expected[index]);
		return -1;
	}
	index++;

	if (i < NUM_LONGJMPS)
		longjmp(jmp_buf, i + 1);	

	return 0;

>  
> -    printf("done\n");
> +    printf("Test %s\n", had_errors ? "FAILED" : "PASSED");
>      return 0;
>  }
> -- 
> 2.23.0.162.g0b9fbb3734-goog
>