test: added tests for validating webhook analyzer (#996)

This commit introduces comprehensive tests for the validating webhook
analyzer defined in the `pkg/analyzer` package.

Adding these tests increases the code coverage of the
`validating_webhook.go` file to almost 95%.

Partially addresses: https://github.com/k8sgpt-ai/k8sgpt/issues/889

Signed-off-by: VaibhavMalik4187 <vaibhavmalik2018@gmail.com>

pkg/analyzer/validating_webhook_test.go

@@ -0,0 +1,137 @@
+/*
+Copyright 2024 The K8sGPT 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 analyzer
+
+import (
+	"context"
+	"testing"
+
+	"github.com/k8sgpt-ai/k8sgpt/pkg/common"
+	"github.com/k8sgpt-ai/k8sgpt/pkg/kubernetes"
+	"github.com/stretchr/testify/require"
+	admissionregistrationv1 "k8s.io/api/admissionregistration/v1"
+	v1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/client-go/kubernetes/fake"
+)
+
+func TestValidatingWebhookAnalyzer(t *testing.T) {
+	config := common.Analyzer{
+		Client: &kubernetes.Client{
+			Client: fake.NewSimpleClientset(
+				&v1.Pod{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "Pod1",
+						Namespace: "default",
+						Labels: map[string]string{
+							"pod": "Pod1",
+						},
+					},
+				},
+				&v1.Service{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "test-service1",
+						Namespace: "default",
+					},
+					Spec: v1.ServiceSpec{
+						Selector: map[string]string{
+							"pod": "Pod1",
+						},
+					},
+				},
+				&v1.Service{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "test-service2",
+						Namespace: "test",
+					},
+					Spec: v1.ServiceSpec{
+						// No such pod exists in the test namespace
+						Selector: map[string]string{
+							"pod": "Pod2",
+						},
+					},
+				},
+				&v1.Service{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "test-service3",
+						Namespace: "test",
+					},
+					Spec: v1.ServiceSpec{
+						// len(service.Spec.Selector) == 0
+						Selector: map[string]string{},
+					},
+				},
+				&admissionregistrationv1.ValidatingWebhookConfiguration{
+					ObjectMeta: metav1.ObjectMeta{
+						Name:      "test-validating-webhook-config",
+						Namespace: "test",
+					},
+					Webhooks: []admissionregistrationv1.ValidatingWebhook{
+						{
+							Name: "webhook1",
+							ClientConfig: admissionregistrationv1.WebhookClientConfig{
+								Service: &admissionregistrationv1.ServiceReference{
+									Name:      "test-service1",
+									Namespace: "default",
+								},
+							},
+						},
+						{
+							// No pod exists in the test namespace
+							Name: "webhook2",
+							ClientConfig: admissionregistrationv1.WebhookClientConfig{
+								Service: &admissionregistrationv1.ServiceReference{
+									Name:      "test-service2",
+									Namespace: "test",
+								},
+							},
+						},
+						{
+							Name: "webhook3",
+							ClientConfig: admissionregistrationv1.WebhookClientConfig{
+								Service: &admissionregistrationv1.ServiceReference{
+									Name:      "test-service3",
+									Namespace: "test",
+								},
+							},
+						},
+						{
+							// Service doesn't exist.
+							Name: "webhook4",
+							ClientConfig: admissionregistrationv1.WebhookClientConfig{
+								Service: &admissionregistrationv1.ServiceReference{
+									Name:      "test-service4-doesn't-exist",
+									Namespace: "test",
+								},
+							},
+						},
+						{
+							// Service is nil.
+							Name:         "webhook5",
+							ClientConfig: admissionregistrationv1.WebhookClientConfig{},
+						},
+					},
+				},
+			),
+		},
+		Context:   context.Background(),
+		Namespace: "default",
+	}
+	resultsLen := 3
+
+	vwAnalyzer := ValidatingWebhookAnalyzer{}
+	results, err := vwAnalyzer.Analyze(config)
+	require.NoError(t, err)
+	require.Equal(t, resultsLen, len(results))
+}