test: verify json format passed through varlink

This drops logs of failed unit tests in TEST-02-UNITTESTS from the journal,
as the expected logs from test-varlink-idl makes the post script fail.
Saving logs in journal is simply noisy, and we will output anyway after
qemu or nspawn finished by check_result_{qemu,nspawn}_unittests().

test/units/end.service

@@ -7,5 +7,5 @@ OnFailureJobMode=replace-irreversibly
 
 [Service]
 Type=oneshot
-ExecStart=/bin/sh -x -c 'systemctl poweroff --no-block'
+ExecStart=/usr/lib/systemd/tests/testdata/units/end.sh
 TimeoutStartSec=5m

test/units/end.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+set -eux
+set -o pipefail
+
+(! journalctl -q -o short-monotonic --grep "didn't pass validation" >>/failed)
+
+systemctl poweroff --no-block
+exit 0

test/units/testsuite-02.sh

@@ -63,9 +63,6 @@ report_result() {
         echo "$name OK"
         echo "$name" >>/testok
     fi
-
-    systemd-cat echo "--- $name ---"
-    systemd-cat cat "/$name.log"
 }
 
 set +x