test/integration: boot scenario for the everyday boot

Boots the installed system a second time, records the time to SSH and
systemd-analyze, and asserts systemd reaches running with no failed
units. It gives CI a scenario that passes on today's installer and a
number for every change that touches boot.

test/integration.d/boot-test.sh

@@ -0,0 +1,34 @@
+#!/bin/bash
+#
+# Everyday boot: boots the installed system a second time and records how
+# long it takes to answer SSH and what systemd-analyze reports, then asserts
+# that systemd finished starting with no failed units. CI reports these next
+# to the install time, so a change that slows booting shows up in its PR.
+
+source "$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)/base-test.sh"
+
+base_image_ready || { echo "No base image; run this through ./test/integration" >&2; exit 1; }
+
+log "Booting the installed system"
+boot_started=$(date +%s%N)
+start_vm_from_base
+wait_for_ssh 300 failure-boot-ssh-timeout || exit 1
+boot_ms=$((($(date +%s%N) - boot_started) / 1000000))
+# Coarse: wait_for_ssh polls every 5 s. systemd-analyze below has the exact
+# firmware, loader, kernel and userspace split.
+log "SSH answered within ${boot_ms} ms of power-on"
+
+# --wait returns once startup has finished, so systemd-analyze has final
+# numbers and a unit that fails late in boot is still counted.
+state=$(ssh_guest "timeout 120 systemctl is-system-running --wait" 2>/dev/null | tr -d '\r')
+ssh_guest "systemd-analyze" >"$RUN_DIR/systemd-analyze.txt" 2>/dev/null || true
+ssh_guest "systemd-analyze blame --no-pager | head -n 20" >"$RUN_DIR/systemd-analyze-blame.txt" 2>/dev/null || true
+ssh_guest "systemctl --failed --no-legend --plain" >"$RUN_DIR/failed-units.txt" 2>/dev/null || true
+printf '{"boot_to_ssh_ms": %d, "system_state": "%s"}\n' "$boot_ms" "$state" >"$RUN_DIR/boot-timing.json"
+
+check "systemd reports the system running (got: ${state:-nothing})" test "$state" = running
+check "no failed units" test ! -s "$RUN_DIR/failed-units.txt"
+capture_console "success-boot"
+
+stop_vm
+finish