Subject: Re: [PATCH] t1050-large: replace dd by test-genrandom

From: Junio C Hamano <[email-masked]>
Date: Wed, 14 Jan 2015 09:31:06 -0800

Jeff King <[email-masked]> writes:

> On Tue, Jan 13, 2015 at 03:40:10PM -0800, Junio C Hamano wrote:
>
>> >> -	test-genrandom seed2 2500000 >huge &&
>> >> +	printf "\0%2500000s" Y >huge &&
>> [...]
>> Are we depending on the binary-ness of these test files by the way?
>> The leading NUL \0 looked a bit strange to me.
>
> I don't think so. We do not want to do a text diff, because that would
> overflow our GIT_ALLOC_LIMIT. But the core.bigfilethreshold check is
> what will make them binary, not the actual content. So a gigantic text
> file is arguably a better test of the feature in question.

Perhaps.

The original used "dd seek" primarily so that we can logically have
large file without wasting diskspace, in addition to make sure that
the result would compress well.  The large printf will still waste
the diskspace, but disks are cheap enough to tolerate a hanful of
files of a few megabytes and you already made sure that the
compressibility is what matters more to the test latency, so I think
all is good.

Thanks.