From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 27 Feb 2018 22:42:25 GMT
Subject: Re: [PATCH v3 4/9] t3701: don't hard code sha1 hash values
Message-ID: <xmqqinainjfy.fsf@gitster-ct.c.googlers.com>
In-Reply-To: <20180227110404.16816-5-phillip.wood@talktalk.net>

Phillip Wood <phillip.wood@talktalk.net> writes:

>  t/t3701-add-interactive.sh | 30 ++++++++++++++++++++----------
>  1 file changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
> index bdd1f292a9..46d655038f 100755
> --- a/t/t3701-add-interactive.sh
> +++ b/t/t3701-add-interactive.sh
> @@ -10,6 +10,16 @@ then
>  	test_done
>  fi
>  
> +diff_cmp () {
> +	for x
> +	do
> +		sed  -e '/^index/s/[0-9a-f]*[1-9a-f][0-9a-f]*\.\./1234567../' \
> +		     -e '/^index/s/\.\.[0-9a-f]*[1-9a-f][0-9a-f]*/..9abcdef/' \
> +		     "$x" >"$x.filtered"

Interesting ;-)  You require .. and on the left hand side you want
to see a run of hexdec with at least one non-zero hexdigit, which is
filtered to fixed-length 1234567; right hand side is the same deal.

Which sounds like a reasonable way to future-proof the comparison.

If 7 zeros are expected in the result, and the actual output had 8
zeros, the filter does not touch either so they compare differently,
which is somewhat unfortunate.  Perhaps something like

	/^index/s/^00*\.\./0000000../
	/^index/s/\([^0-9a-f]\)00*\.\./\10000000../
	/^index/s/\.\.00*$/..0000000/
	/^index/s/\.\.00*\([^0-9a-f]\)/..0000000\1/

after the above two patterns help?