test(net): add the doctor control-plane repair scenarios and runner

net Phase 1's three privileged fixes (unmask-nm, disable-rival, chmod-keyfile) can't be verified against fakes past the point where real sudo and a running NetworkManager matter, and the broken states they repair are too dangerous to stage on a daily driver. I added the live-verification harness they need.

Three scenario files encode the break/fix/assert for each: mask NetworkManager, enable a rival dhcpcd, and chmod a profile keyfile to 0644, then run the real net doctor --fix and assert the repair. Each also names the read-only diagnose verdict it expects, so a run that breaks catches whether the fault is in the diagnosis or the fix. run-net-scenarios.sh rsyncs the net and panelkit trees into a target VM over ssh and drives the scenarios there.

The target is a booted VM, not a container: NetworkManager needs a real kernel and network stack to actually run, so an nspawn container can only show the filesystem-level half (the mask symlink, the keyfile mode) and not "NM is active". A disposable VM you revert is the right environment.

The scenario break/fix/assert logic is the reviewed part. The ssh transport plumbing hasn't been exercised against a live target yet, so it's marked first-draft and may need a shakeout on the first real run. The by-hand equivalent already lives in the manual-testing checklist.

1 files changed, 29 insertions, 0 deletions

diff --git a/scripts/testing/net-scenarios/10-nm-masked.sh b/scripts/testing/net-scenarios/10-nm-masked.sh
new file mode 100644
index 0000000..d3b382b
--- /dev/null
+++ b/scripts/testing/net-scenarios/10-nm-masked.sh
@@ -0,0 +1,29 @@
+# shellcheck shell=bash disable=SC2034  # sourced by run-net-scenarios.sh
+# Scenario: a masked NetworkManager is unmasked and started.
+#
+# Masking NetworkManager makes the generic "isn't running" verdict useless —
+# systemctl can't start a masked unit — so the doctor must name the mask and
+# unmask first. Break by masking; the fix's chain should unmask then start.
+SCENARIO_DESC="masked NetworkManager is unmasked and started"
+SCENARIO_GROUP="control-plane"
+
+scenario_break() {
+    nexec "systemctl mask NetworkManager"
+}
+
+# The verdict the read-only diagnose should produce before any fix runs.
+scenario_diagnose_expect() {
+    ndoctor_json ".outcome" | grep -qx fixable \
+        && ndoctor_json '.report.control_plane.nm_state' | grep -qx masked
+}
+
+scenario_fix() {
+    nfix   # net doctor --fix
+}
+
+scenario_assert() {
+    # Unmasked (the state flip, testable anywhere) AND active (needs a real
+    # NetworkManager, so a container without netlink can only show the unmask).
+    ! nexec "systemctl is-enabled NetworkManager | grep -qx masked" \
+        && nexec "systemctl is-active NetworkManager >/dev/null"
+}