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

[Fabian Stelzer <fs@gigacodes.de>]

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
-- 
2.33.1