Re: [PATCH] t/gpg: simplify test for unknown key

> To test for a key that is completely unknown to the keyring we need one
> to sign the commit with. This was done by generating a new key and not
> add it into the keyring. To avoid the key generation overhead and
> problems where GPG did hang in CI during it, switch GNUPGHOME to an
> empty directory instead, therefore making all used keys unknown for this
> single `verify-commit` call.
>
> Reported-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
> Signed-off-by: Fabian Stelzer <fs@gigacodes.de>
> ---
> This was reported by Ævar in <211222.86ilvhpbl0.gmgdl@evledraar.gmail.com>.
> Just using an empty keyring / gpg homedir should achieve the same effect and 
> keeps the stress of generating a gpg key out of the CI.

>
>
>  t/t7510-signed-commit.sh | 22 ++--------------------
>  1 file changed, 2 insertions(+), 20 deletions(-)
>
> diff --git a/t/t7510-signed-commit.sh b/t/t7510-signed-commit.sh
> index 9882b69ae2..2d38580847 100755
> --- a/t/t7510-signed-commit.sh
> +++ b/t/t7510-signed-commit.sh
> @@ -71,25 +71,7 @@ test_expect_success GPG 'create signed commits' '
>  	git tag eleventh-signed $(cat oid) &&
>  	echo 12 | git commit-tree --gpg-sign=B7227189 HEAD^{tree} >oid &&
>  	test_line_count = 1 oid &&
> -	git tag twelfth-signed-alt $(cat oid) &&
> -
> -	cat >keydetails <<-\EOF &&
> -	Key-Type: RSA
> -	Key-Length: 2048
> -	Subkey-Type: RSA
> -	Subkey-Length: 2048
> -	Name-Real: Unknown User
> -	Name-Email: unknown@git.com
> -	Expire-Date: 0
> -	%no-ask-passphrase
> -	%no-protection
> -	EOF
> -	gpg --batch --gen-key keydetails &&
> -	echo 13 >file && git commit -a -S"unknown@git.com" -m thirteenth &&
> -	git tag thirteenth-signed &&
> -	DELETE_FINGERPRINT=$(gpg -K --with-colons --fingerprint --batch unknown@git.com | grep "^fpr" | head -n 1 | awk -F ":" "{print \$10;}") &&
> -	gpg --batch --yes --delete-secret-keys $DELETE_FINGERPRINT &&
> -	gpg --batch --yes --delete-keys unknown@git.com
> +	git tag twelfth-signed-alt $(cat oid)
>  '
>  
>  test_expect_success GPG 'verify and show signatures' '
> @@ -129,7 +111,7 @@ test_expect_success GPG 'verify and show signatures' '
>  '
>  
>  test_expect_success GPG 'verify-commit exits failure on unknown signature' '
> -	test_must_fail git verify-commit thirteenth-signed 2>actual &&
> +	GNUPGHOME=./empty_home test_must_fail git verify-commit initial 2>actual &&
>  	! grep "Good signature from" actual &&
>  	! grep "BAD signature from" actual &&
>  	grep -q -F -e "No public key" -e "public key not found" actual