Subject: Re: [PATCH 2/2] bundle tests: use test_cmp instead of grep

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Thu, 22 Jul 2021 01:53:54 +0200

On Tue, Jul 20 2021, Taylor Blau wrote:

> On Tue, Jul 20, 2021 at 01:52:09PM +0200, Ævar Arnfjörð Bjarmason wrote:
>> So let's use test_cmp instead, and also in the other nearby tests
>> where it's easy.
>
> I took a look at this patch carefully to make sure that this
> transformation also improved the readability, too.
>
> Looking around, I think that this was a good improvement in readability,
> but also hardened the tests (for the reasons that you mentioned). One
> tiny note below.
>
>>  test_expect_success 'empty bundle file is rejected' '
>> @@ -67,11 +83,33 @@ test_expect_success 'ridiculously long subject in boundary' '
>>  	printf "%01200d\n" 0 | git commit -F - &&
>>  	test_commit fifth &&
>>  	git bundle create long-subject-bundle.bdl HEAD^..HEAD &&
>> -	git bundle list-heads long-subject-bundle.bdl >heads &&
>> -	test -s heads &&
>> +	cat >expect <<-EOF &&
>> +	$(git rev-parse main) HEAD
>> +	EOF
>> +	git bundle list-heads long-subject-bundle.bdl >actual &&
>> +	test_cmp expect actual &&
>
> This is quite readable, but the assertion below gets much more
> complicated as a result of the change.
>
>>  	git fetch long-subject-bundle.bdl &&
>> -	sed -n "/^-/{p;q;}" long-subject-bundle.bdl >boundary &&
>> -	grep "^-$OID_REGEX " boundary
>> +
>> +	cat >expect.common <<-EOF &&
>> +	-$(git log --pretty=format:"%H %s" -1 HEAD^)
>> +	$(git rev-parse HEAD) HEAD
>> +	EOF
>> +	if test_have_prereq SHA1
>> +	then
>> +		cp expect.common expect
>> +	else
>> +		echo @object-format=sha256 >expect
>> +		cat expect.common >>expect
>> +	fi &&
>
> Here we're setting up expect, but I think flipping the order might make
> things a little easier to follow. Maybe something like this:
>
>     rm expect &&
>     if ! test_have_prereq SHA1
>     then
>       echo "@object-format=sha256" >expect
>     fi &&
>     cat >>expect <<-EOF &&
>     -$(git log --pretty=format:"%H %s" -1 HEAD^)
>     $(git rev-parse HEAD) HEAD
>     EOF &&

Thanks, I used pretty much that as-is for v2.

> Or, if you wanted to go further, you could do something like:
>
>     cat >expect <<-EOF
>     $(test_have_prereq SHA1 || echo "@object-format=sha256")
>     -$(git log --pretty=format:"%H %s" -1 HEAD^)
>     $(git rev-parse HEAD) HEAD
>     EOF
>
> which is arguably a little tighter (although I find the
> echo-in-a-heredoc thing to be kind of ugly).

This one won't work because you'll have an empty line at the start under
SHA-1.

>> +	if test_have_prereq SHA1
>> +	then
>> +		head -n 3 long-subject-bundle.bdl >bundle-header
>> +	else
>> +		head -n 4 long-subject-bundle.bdl >bundle-header
>> +	fi &&
>> +	grep -v "^#" bundle-header >actual &&
>
> Here I would suggest getting rid of the bundle-header intermediary and
> instead writing:
>
>     if test_have_prereq SHA1
>     then
>       head -n 3 long-subject-bundle.bdl
>     else
>       head -n 4 long-subject-bundle.bdl
>     fi | grep -v "^#" >actual
>
> and then having your

Thanks, used that.