hook tests: turn exit code assertions into a loop

Amend a test added in 96e7225b31 (hook: add 'run' subcommand,
2021-12-22) to use a for-loop instead of a copy/pasting the same test
for the four exit codes we test.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1800-hook.sh

@@ -53,31 +53,16 @@ test_expect_success 'git hook run: stdout and stderr both write to our stderr' '
 	test_must_be_empty stdout.actual
 '
 
-test_expect_success 'git hook run: exit codes are passed along' '
-	write_script .git/hooks/test-hook <<-EOF &&
-	exit 1
-	EOF
+for code in 1 2 128 129
+do
+	test_expect_success "git hook run: exit code $code is passed along" '
+		test_hook test-hook <<-EOF &&
+		exit $code
+		EOF
 
-	test_expect_code 1 git hook run test-hook &&
-
-	write_script .git/hooks/test-hook <<-EOF &&
-	exit 2
-	EOF
-
-	test_expect_code 2 git hook run test-hook &&
-
-	write_script .git/hooks/test-hook <<-EOF &&
-	exit 128
-	EOF
-
-	test_expect_code 128 git hook run test-hook &&
-
-	write_script .git/hooks/test-hook <<-EOF &&
-	exit 129
-	EOF
-
-	test_expect_code 129 git hook run test-hook
-'
+		test_expect_code $code git hook run test-hook
+	'
+done
 
 test_expect_success 'git hook run arg u ments without -- is not allowed' '
 	test_expect_code 129 git hook run test-hook arg u ments