Re: [Qemu-devel] [PATCH v4 16/20] hbitmap: truncate tests

[Max Reitz <mreitz@redhat.com>]

On 2015-03-20 at 15:16, John Snow wrote:
> The general approach is to set bits close to the boundaries of
> where we are truncating and ensure that everything appears to
> have gone OK.
>
> We test growing and shrinking by different amounts:
> - Less than the granularity
> - Less than the granularity, but across a boundary
> - Less than sizeof(unsigned long)
> - Less than sizeof(unsigned long), but across a ulong boundary
> - More than sizeof(unsigned long)
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> Reviewed-by: Max Reitz <mreitz@redhat.com>
> ---
>   tests/test-hbitmap.c | 255 +++++++++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 255 insertions(+)
>
> diff --git a/tests/test-hbitmap.c b/tests/test-hbitmap.c
> index 8c902f2..9f41b5f 100644
> --- a/tests/test-hbitmap.c
> +++ b/tests/test-hbitmap.c

[snip]

> +
> +static void hbitmap_test_check_boundary_bits(TestHBitmapData *data)
> +{
> +    size_t size = MIN(data->size, data->old_size);
> +
> +    if (data->granularity == 0) {
> +        hbitmap_test_check_get(data);
> +        hbitmap_test_check(data, 0);
> +    } else {
> +        /* If a granularity was set, note that every distinct
> +         * (bit >> granularity) value that was set will increase
> +         * the bit pop count by 2^granularity, not just 1.
> +         *
> +         * The hbitmap_test_check facility does not currently tolerate
> +         * non-zero granularities, so test the boundaries and the population
> +         * count manually.
> +         */

Thanks!

Max