--- /dev/null
+#!/usr/bin/env bash
+# SPDX-License-Identifier: LGPL-2.1-or-later
+set -eux
+set -o pipefail
+
+# shellcheck source=test/units/assert.sh
+. "$(dirname "$0")"/assert.sh
+
+systemd-id128 --help
+systemd-id128 help
+systemd-id128 show
+systemd-id128 show --pretty | tail -n10
+systemd-id128 show 4f68bce3e8cd4db196e7fbcaf984b709 # root-x86-64
+systemd-id128 show --pretty 4f68bce3e8cd4db196e7fbcaf984b709
+
+[[ "$(systemd-id128 new | wc -c)" -eq 33 ]]
+systemd-id128 new -p
+systemd-id128 new -u
+systemd-id128 new -a 4f68bce3e8cd4db196e7fbcaf984b709
+
+systemd-id128 machine-id
+systemd-id128 machine-id --pretty
+systemd-id128 machine-id --uuid
+systemd-id128 machine-id --app-specific=4f68bce3e8cd4db196e7fbcaf984b709
+assert_eq "$(systemd-id128 machine-id)" "$(</etc/machine-id)"
+
+systemd-id128 boot-id
+systemd-id128 boot-id --pretty
+systemd-id128 boot-id --uuid
+systemd-id128 boot-id --app-specific=4f68bce3e8cd4db196e7fbcaf984b709
+assert_eq "$(systemd-id128 boot-id --uuid)" "$(</proc/sys/kernel/random/boot_id)"
+
+# shellcheck disable=SC2016
+systemd-run --wait --pipe bash -euxc '[[ $INVOCATION_ID == "$(systemd-id128 invocation-id)" ]]'
+
+(! systemd-id128)
+(! systemd-id128 new -a '')
+(! systemd-id128 new -a '0')
+(! systemd-id128 invocation-id -a 4f68bce3e8cd4db196e7fbcaf984b709)
+(! systemd-id128 show '')
+(! systemd-id128 show "$(set +x; printf '%0.s0' {0..64})")