Let a node agent hear the creation of the seat's placement and candidates, so it binds them with no timer (ADR 0567 §9, issue 1126)

go/buscompose/buscompose_test.go

@@ -35,7 +35,7 @@ func beyondTheControllers(user string) map[string]bool {
 	if !ok {
 		return out
 	}
-	for _, s := range append(readGrants("node-engine_have", "*.node"), NodeComposeReads(node)...) {
+	for _, s := range append(append(readGrants("node-engine_have", "*.node"), NodeComposeReads(node)...), NodeComposeAdvisories()...) {
 		out[s] = true
 	}
 	return out
@@ -129,6 +129,11 @@ func TestTheCopiedComposerComposesAsTheControllers(t *testing.T) {
 			t.Errorf("a node is granted %s: %v, want %v", bucket, !granted, granted)
 		}
 	}
+	// It hears the creation of those two buckets, and of no other.
+	if got := NodeComposeAdvisories(); len(got) != 2 || got[0] != "$JS.EVENT.ADVISORY.STREAM.CREATED.KV_mesh-delivery-assigner_placement" ||
+		got[1] != "$JS.EVENT.ADVISORY.STREAM.CREATED.KV_mesh-delivery-assigner_candidates" {
+		t.Errorf("a node hears the creation of %v", got)
+	}
 	raw, err := os.ReadFile(filepath.Join("testdata", "controller-user-lists.json"))
 	if err != nil {
 		t.Fatal(err)