tests: add a few integration tests.

tests/integration/systemd/journalctl.bats

@@ -0,0 +1,30 @@
+#!/usr/bin/env bats
+# apparmor.d - Full set of apparmor profiles
+# Copyright (C) 2025 Alexandre Pujol <alexandre@pujol.io>
+# SPDX-License-Identifier: GPL-2.0-only
+
+load ../common
+
+@test "journalctl: Show all messages with priority level 3 (errors) from this boot" {
+    sudo journalctl -b --priority=3
+}
+
+@test "journalctl: Show only the last N lines of the journal" {
+    sudo journalctl --lines 100
+}
+
+@test "journalctl: Show all messages by a specific [u]nit" {
+    sudo journalctl --unit apparmor.service
+}
+
+@test "journalctl: Show all messages by a specific process" {
+    sudo journalctl _PID=1
+}
+
+@test "journalctl: Show all messages by a specific executable" {
+    sudo journalctl /usr/bin/bootctl
+}
+
+@test "journalctl: Delete journal logs which are older than 10 seconds" {
+    sudo journalctl --vacuum-time=10s
+}