Re: [PATCH v3 18/25] t5326: test multi-pack bitmap behavior

On Thu, Aug 12, 2021 at 06:38:20PM -0400, Taylor Blau wrote:

quoted

This is brittle with respect to Git's delta heuristics, of course, but I
don't think there's a better way to do it with pack-objects. And this is
not the first test to make similar assumptions. I think you can
construct a known set of deltas using lib-pack.sh. It may get a bit
complicated. As an alternative, maybe it makes sense to confirm that the
deltas are set up as expected? You can do it with cat-file
--batch-check.

Yeah, I definitely agree that this test is brittle. But it would fail if
our assumptions about what gets delta'd with what changes, because we do
check that 'a' is a delta on top of 'b' (see the call to have_delta
towards the end of this test). That have_delta helper does use
`--batch-check=%(deltabase)`, which is (I think) the cat-file invocation
you're mentioning.

Doh, I totally missed that. I was expecting to verify it earlier in the
test as a pre-condition, but it works just fine where it is. So yeah,
you are already doing the thing I was suggesting.

-Peff