diff --git a/webhook/webhook_suite_test.go b/webhook/webhook_suite_test.go
index 593f2eba6..7d0e7f09f 100644
--- a/webhook/webhook_suite_test.go
+++ b/webhook/webhook_suite_test.go
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package main_test
+package main
 
 import (
 	"testing"
diff --git a/webhook/webhook_test.go b/webhook/webhook_test.go
index d55d39f0c..f44bbde0d 100644
--- a/webhook/webhook_test.go
+++ b/webhook/webhook_test.go
@@ -12,23 +12,93 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package main_test
+package main
 
 import (
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/ginkgo/extensions/table"
 	. "github.com/onsi/gomega"
 
+  "bytes"
+  "net/http"
+  "net/http/httptest"
+
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+  "k8s.io/api/admission/v1beta1"
 
 	"github.com/intel/multus-cni/types"
-	. "github.com/intel/multus-cni/webhook"
 )
 
 var _ = Describe("Webhook", func() {
+
+  Describe("Preparing Admission Review Response", func() {
+    Context("Admission Review Request is nil", func() {
+      It("should return error", func() {
+        ar := &v1beta1.AdmissionReview{}
+        ar.Request = nil
+        Expect(prepareAdmissionReviewResponse(false, "", ar)).To(HaveOccurred())
+      })
+    })
+    Context("Message is not empty", func() {
+      It("should set message in the response", func() {
+        ar := &v1beta1.AdmissionReview{}
+        ar.Request = &v1beta1.AdmissionRequest{
+          UID: "fake-uid",
+        }
+        err := prepareAdmissionReviewResponse(false, "some message", ar)
+        Expect(err).NotTo(HaveOccurred())
+        Expect(ar.Response.Result.Message).To(Equal("some message"))
+      })
+    })
+  })
+
+  Describe("Deserializing Admission Review", func() {
+    Context("It's not an Admission Review", func() {
+      It("should return an error", func() {
+        body := []byte("some-invalid-body")
+        _, err := deserializeAdmissionReview(body)
+        Expect(err).To(HaveOccurred())
+      })
+    })
+  })
+
+  Describe("Deserializing Network Attachment Definition", func() {
+    Context("It's not an Network Attachment Definition", func() {
+      It("should return an error", func() {
+        ar := &v1beta1.AdmissionReview{}
+        ar.Request = &v1beta1.AdmissionRequest{}
+        _, err := deserializeNetworkAttachmentDefinition(*ar)
+        Expect(err).To(HaveOccurred())
+      })
+    })
+  })
+
+  Describe("Handling validation request", func() {
+    Context("Request body is empty", func() {
+      It("should return an error", func() {
+        req := httptest.NewRequest("POST", "https://fakewebhook/validate", nil)
+        w := httptest.NewRecorder()
+        validateHandler(w, req)
+        resp := w.Result()
+        Expect(resp.StatusCode).To(Equal(http.StatusBadRequest))
+      })
+    })
+
+    Context("Content type is not application/json", func() {
+      It("should return an error", func() {
+        req := httptest.NewRequest("POST", "https://fakewebhook/validate", bytes.NewBufferString("fake-body"))
+        req.Header.Set("Content-Type", "invalid-type")
+        w := httptest.NewRecorder()
+        validateHandler(w, req)
+        resp := w.Result()
+        Expect(resp.StatusCode).To(Equal(http.StatusUnsupportedMediaType))
+      })
+    })
+  })
+
 	DescribeTable("Network Attachment Definition validation",
 		func(in types.NetworkAttachmentDefinition, out bool, shouldFail bool) {
-			actualOut, err := ValidateNetworkAttachmentDefinition(in)
+			actualOut, err := validateNetworkAttachmentDefinition(in)
 			Expect(actualOut).To(Equal(out))
 			if shouldFail {
 				Expect(err).To(HaveOccurred())