tests/staged-delay.sh: New test

Attempting to reproduce
https://bugzilla.redhat.com/show_bug.cgi?id=1827712
but no dice yet.

tests/kola/destructive/staged-delay.sh

@@ -0,0 +1,40 @@
+#!/bin/bash
+set -xeuo pipefail
+
+# Add an artificial delay into ostree-finalize-staged.service
+# and verify it sees /boot; https://bugzilla.redhat.com/show_bug.cgi?id=1827712
+
+. ${KOLA_EXT_DATA}/libinsttest.sh
+
+require_writable_sysroot
+prepare_tmpdir
+
+n=$(nth_boot)
+case "${n}" in
+1)
+dropin=/etc/systemd/system/ostree-finalize-staged.service.d/delay.conf
+mkdir -p $(dirname ${dropin})
+cat >"${dropin}" << 'EOF'
+[Service]
+ExecStop=/bin/sh -c 'sleep 10 && if ! test -d /boot/loader/entries; then echo error: no /boot/loader/entries; exit 1; fi; echo ostree-finalize-staged found /boot/loader/entries'
+#ExecStop=/bin/false
+EOF
+systemctl daemon-reload
+rpm-ostree kargs --append=somedummykarg=1
+kola_reboot
+;;
+
+2)
+journalctl -b -1 -u ostree-finalize-staged > logs.txt
+assert_file_has_content_literal logs.txt 'ostree-finalize-staged found /boot/loader/entries'
+# older systemd doesn't output the success message
+if systemctl --version | head -1 | grep -qF -e 'systemd 239'; then
+  assert_file_has_content_literal logs.txt 'Stopped OSTree Finalize Staged Deployment'
+  assert_not_file_has_content logs.txt 'Failed with result'
+else
+  assert_file_has_content_literal logs.txt 'ostree-finalize-staged.service: Succeeded.'
+fi
+assert_file_has_content_literal /proc/cmdline somedummykarg=1 
+;;
+esac
+echo ok