Fix ugly but non functional error messages in maintenance contolller

plus tests for the maintenance controller

Author: marwinski

pkg/controller/maintenance/add.go

@@ -62,23 +62,41 @@ func (r *Reconciler) AddToManager(mgr manager.Manager) error {
 // ShootPredicate returns the predicates for the core.gardener.cloud/v1beta1.Shoot watch.
 func (r *Reconciler) ShootPredicate() predicate.Predicate {
 	return predicate.Funcs{
+		CreateFunc: func(e event.CreateEvent) bool {
+			shoot, ok := e.Object.(*gardencorev1beta1.Shoot)
+			if !ok {
+				return false
+			}
+			return hasFalcoLabel(shoot)
+		},
 		UpdateFunc: func(e event.UpdateEvent) bool {
 			shoot, ok := e.ObjectNew.(*gardencorev1beta1.Shoot)
 			if !ok {
-				return ok
+				return false
+			}
+
+			if !hasFalcoLabel(shoot) {
+				return false
 			}
 
 			oldShoot, ok := e.ObjectOld.(*gardencorev1beta1.Shoot)
 			if !ok {
-				return ok
+				return false
 			}
-			maintain := (hasMaintainNowAnnotation(shoot) && !hasMaintainNowAnnotation(oldShoot)) ||
-				!apiequality.Semantic.DeepEqual(oldShoot.Spec.Maintenance.TimeWindow, shoot.Spec.Maintenance.TimeWindow)
 
-			key := "extensions.extensions.gardener.cloud/shoot-falco-service"
-			val, ok := shoot.Labels[key]
-
-			return maintain && ok && val == "true"
+			return (hasMaintainNowAnnotation(shoot) && !hasMaintainNowAnnotation(oldShoot)) ||
+				!apiequality.Semantic.DeepEqual(oldShoot.Spec.Maintenance.TimeWindow, shoot.Spec.Maintenance.TimeWindow)
+		},
+		DeleteFunc: func(_ event.DeleteEvent) bool {
+			return false
+		},
+		GenericFunc: func(_ event.GenericEvent) bool {
+			return false
 		},
 	}
 }
+
+func hasFalcoLabel(shoot *gardencorev1beta1.Shoot) bool {
+	val, ok := shoot.Labels["extensions.extensions.gardener.cloud/shoot-falco-service"]
+	return ok && val == "true"
+}

pkg/controller/maintenance/export_test.go

@@ -0,0 +1,12 @@
+// SPDX-FileCopyrightText: 2026 SAP SE or an SAP affiliate company and Gardener contributors
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package maintenance
+
+import "github.com/gardener/gardener-extension-shoot-falco-service/pkg/admission/mutator"
+
+// SetMutator sets the mutator on the reconciler (test-only export).
+func (r *Reconciler) SetMutator(m *mutator.Shoot) {
+	r.mutator = m
+}

pkg/controller/maintenance/helpers_test.go

@@ -0,0 +1,32 @@
+// SPDX-FileCopyrightText: 2026 SAP SE or an SAP affiliate company and Gardener contributors
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package maintenance_test
+
+import (
+	gardencorev1beta1 "github.com/gardener/gardener/pkg/apis/core/v1beta1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	crfake "sigs.k8s.io/controller-runtime/pkg/client/fake"
+
+	"github.com/gardener/gardener-extension-shoot-falco-service/pkg/admission/mutator"
+	"github.com/gardener/gardener-extension-shoot-falco-service/pkg/controller/maintenance"
+)
+
+func setMutator(r *maintenance.Reconciler, m *mutator.Shoot) {
+	r.SetMutator(m)
+}
+
+func newFakeClientWithShoot(scheme *runtime.Scheme, shoot *gardencorev1beta1.Shoot) client.Client {
+	b := crfake.NewClientBuilder().WithScheme(scheme)
+	if shoot != nil {
+		b = b.WithObjects(shoot)
+	}
+	return b.Build()
+}
+
+type fakeRecorder struct{}
+
+func (r *fakeRecorder) Eventf(_ runtime.Object, _ runtime.Object, _, _, _, _ string, _ ...interface{}) {
+}

pkg/controller/maintenance/maintenance_suite_test.go

@@ -0,0 +1,17 @@
+// SPDX-FileCopyrightText: 2026 SAP SE or an SAP affiliate company and Gardener contributors
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package maintenance_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo/v2"
+	. "github.com/onsi/gomega"
+)
+
+func TestMaintenance(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Maintenance Controller Suite")
+}