Unreleased: host_busy on GET /backup/status (R-921), a missing tunnel container is 'absent' and not-applicable after an OS update (R-1070), the janitor forces a half-removed vzdump snapshot once (R-1010)

internal/localapi/server_test.go

@@ -13,6 +13,7 @@ import (
 	"testing"
 	"time"
 
+	"gitea.dooplex.hu/admin/felhom-agent/internal/backup"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/hub"
 	"gitea.dooplex.hu/admin/felhom-agent/internal/proxmox"
 )
@@ -514,3 +515,47 @@ func TestBackupStatus_FiltersToThisGuest(t *testing.T) {
 		t.Fatalf("status not scoped to this guest / not latest: %s", w.Body.String())
 	}
 }
+
+// R-921: GET /backup/status says when the host-wide heavy-operation gate is held, so the controller can skip the app
+// stop for a tier the POST would refuse. Free → busy false; held → busy true with the holder's name; the gate not wired
+// → no field at all (the controller's „older agent" reading, never „free").
+//
+// COMPANION RED-PROOF (observed 2026-10-19): with the `resp.HostBusy = …` assignment removed, the held case fails with
+//
+//	server_test.go: free gate: host_busy = <nil>, want busy=false
+//
+// Restored.
+func TestBackupStatus_R921_HostBusy(t *testing.T) {
+	read := func(h http.Handler) *HostBusyState {
+		w := do(t, h, "GET", "/backup/status", "A", "")
+		var resp struct {
+			Data BackupStatusResponse `json:"data"`
+		}
+		if err := json.Unmarshal(w.Body.Bytes(), &resp); err != nil {
+			t.Fatalf("status body: %v (%s)", err, w.Body.String())
+		}
+		return resp.Data.HostBusy
+	}
+	srv := newTestServerS(t, &fakeGuests{}, &fakeBackups{}, &fakeStore{}, nil)
+	if got := read(srv.Handler()); got != nil {
+		t.Fatalf("gate not wired: host_busy = %+v, want absent", got)
+	}
+	gate := &backup.InFlight{}
+	srv.inFlight = gate
+	h := srv.Handler()
+	if got := read(h); got == nil || got.Busy || got.What != "" {
+		t.Fatalf("free gate: host_busy = %+v, want busy=false", got)
+	}
+	release, _, ok := gate.TryAcquire("os-pve-step")
+	if !ok {
+		t.Fatal("could not take the gate")
+	}
+	if got := read(h); got == nil || !got.Busy || got.What != "os-pve-step" {
+		t.Fatalf("held gate: host_busy = %+v, want busy=true what=\"os-pve-step\"", got)
+	}
+	// The read never takes the gate: a POST after the holder lets go is accepted.
+	release()
+	if got := read(h); got == nil || got.Busy {
+		t.Fatalf("released gate: host_busy = %+v, want busy=false", got)
+	}
+}