operator/pkg: test scheme

In this commit, we unit test the init scheme functionality of the operator
by checking that both k8s core scheme and operator v1alpha1 scheme are added.

Signed-off-by: Mohamed Awnallah <mohamedmohey2352@gmail.com>

operator/pkg/scheme/scheme_test.go

@@ -0,0 +1,54 @@
+/*
+Copyright 2024 The Karmada Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package scheme
+
+import (
+	"fmt"
+	"testing"
+
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+
+	operatorv1alpha1 "github.com/karmada-io/karmada/operator/pkg/apis/operator/v1alpha1"
+)
+
+func TestSchemeInitialization(t *testing.T) {
+	// Ensure that the Kubernetes core scheme (for example, Pod) is added.
+	coreGVK := schema.GroupVersionKind{Group: "", Version: "v1", Kind: "Pod"}
+	if !isGVKRegistered(Scheme, coreGVK) {
+		t.Errorf("K8s core scheme should be registered for GVK: %v", coreGVK)
+	}
+
+	// Ensure that the Karmada operator v1alpha1 scheme (for example, Karmada) is added.
+	karmadaGVK := schema.GroupVersionKind{
+		Group:   operatorv1alpha1.GroupVersion.Group,
+		Version: operatorv1alpha1.GroupVersion.Version,
+		Kind:    "Karmada",
+	}
+	if !isGVKRegistered(Scheme, karmadaGVK) {
+		t.Errorf("Karmada v1alpha1 scheme should be registered for GVK: %v", karmadaGVK)
+	}
+}
+
+// isGVKRegistered verifies if the scheme contains a specific GVK.
+func isGVKRegistered(s *runtime.Scheme, gvk schema.GroupVersionKind) bool {
+	_, err := s.New(gvk)
+	if err != nil {
+		fmt.Printf("Failed to find GVK: %v, Error: %v\n", gvk, err)
+	}
+	return err == nil
+}