Re: [PATCH 08/10] t-reftable-block: add tests for log blocks

[Chandra Pratap <chandrapratap3519@gmail.com>]

On Thu, 15 Aug 2024 at 15:11, Patrick Steinhardt <ps@pks.im> wrote:
>
> On Wed, Aug 14, 2024 at 05:33:16PM +0530, Chandra Pratap wrote:
> > @@ -101,9 +101,95 @@ static void t_block_read_write(void)
> >               reftable_record_release(&recs[i]);
> >  }
> >
> > +static void t_log_block_read_write(void)
> > +{
> > +     const int header_off = 21;
> > +     struct reftable_record recs[30];
> > +     const size_t N = ARRAY_SIZE(recs);
> > +     const size_t block_size = 2048;
> > +     struct reftable_block block = { 0 };
> > +     struct block_writer bw = {
> > +             .last_key = STRBUF_INIT,
> > +     };
> > +     struct reftable_record rec = {
> > +             .type = BLOCK_TYPE_LOG,
> > +     };
> > +     size_t i = 0;
> > +     int n;
> > +     struct block_reader br = { 0 };
> > +     struct block_iter it = BLOCK_ITER_INIT;
> > +     struct strbuf want = STRBUF_INIT;
> > +
> > +     REFTABLE_CALLOC_ARRAY(block.data, block_size);
> > +     block.len = block_size;
> > +     block.source = malloc_block_source();
> > +     block_writer_init(&bw, BLOCK_TYPE_LOG, block.data, block_size,
> > +                       header_off, hash_size(GIT_SHA1_FORMAT_ID));
> > +
> > +     for (i = 0; i < N; i++) {
> > +             rec.u.log.refname = xstrfmt("branch%02"PRIuMAX , (uintmax_t)i);
> > +             rec.u.log.update_index = i;
> > +             rec.u.log.value_type = REFTABLE_LOG_UPDATE;
> > +
> > +             recs[i] = rec;
> > +             n = block_writer_add(&bw, &rec);
> > +             rec.u.log.refname = NULL;
> > +             rec.u.log.value_type = REFTABLE_LOG_DELETION;
> > +             check_int(n, ==, 0);
> > +     }
> > +
> > +     n = block_writer_finish(&bw);
> > +     check_int(n, >, 0);
>
> Do we maybe want to rename `n` to `ret`? That's way more customary in
> our codebase.

Sure thing, but then I would want to change the existing test (which gets
renamed as t_ref_block_read_write) and I'm unsure of which patch would
be the most suitable for that change. Would it be fine to include that
change as a part of this patch?

> > +     block_writer_release(&bw);
> > +
> > +     block_reader_init(&br, &block, header_off, block_size, GIT_SHA1_RAWSZ);
> > +
> > +     block_iter_seek_start(&it, &br);
> > +
> > +     for (i = 0; ; i++) {
> > +             int r = block_iter_next(&it, &rec);
> > +             check_int(r, >=, 0);
> > +             if (r > 0)
> > +                     break;
>
> We can also reuse `n` (or `ret`) here, right?
>
> > +             check(reftable_record_equal(&recs[i], &rec, GIT_SHA1_RAWSZ));
> > +     }
>
> One thing that this loop doesn't verify is whether we actually got the
> expected number of log records. It could be that the first iteration
> already returns `r > 0`, which is not our expectation. So we should
> likely add a check for `i == N` after the loop.

What about something like
if (r > 0) {
    check_int(i, ==, N);
    break;
}
That should achieve the same results if I'm not wrong.