Assert the controller's buckets before the served test's fixture writes the chain (issue 1945)

cmd/mesh-controller/composed_served_integration_test.go

@@ -148,6 +148,15 @@ func aServedMesh(t *testing.T) *servedMesh {
 		t.Fatal(err)
 	}
 	t.Cleanup(chainConn.Close)
+	// The controller's own buckets, the chain's among them, as it asserts them at its start.
+	asserter, err := broker.Dial(u.String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(asserter.Close)
+	if err := asserter.EnsureControllerBuckets(); err != nil {
+		t.Fatalf("the controller's buckets: %v", err)
+	}
 	c, err := chain.OnTheBus(ctx, chainConn, func(context.Context) error { return nil })
 	if err != nil {
 		t.Fatal(err)