pkg/webhook: test Interpreter

In this commit, we introduce unit tests for the `Interpreter` webhook
across `Decoder`, `HTTP`, `Injection`, `Response`, and `Webhook` components.

Signed-off-by: Mohamed Awnallah <[email protected]>

pkg/webhook/interpreter/decode.go

@@ -43,7 +43,7 @@ func NewDecoder(scheme *runtime.Scheme) *Decoder {
 // It errors out if req.Object.Raw is empty i.e. containing 0 raw bytes.
 func (d *Decoder) Decode(req Request, into runtime.Object) error {
 	if len(req.Object.Raw) == 0 {
-		return fmt.Errorf("there is no context to decode")
+		return fmt.Errorf("there is no content to decode")
 	}
 	return d.DecodeRaw(req.Object, into)
 }

pkg/webhook/interpreter/decode_test.go

@@ -0,0 +1,277 @@
+/*
+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 interpreter
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	schema "k8s.io/apimachinery/pkg/runtime/schema"
+
+	configv1alpha1 "github.com/karmada-io/karmada/pkg/apis/config/v1alpha1"
+)
+
+type Interface interface {
+	GetAPIVersion() string
+	GetKind() string
+	GetName() string
+}
+
+// MyTestPod represents a simplified version of a Kubernetes Pod for testing purposes.
+// It includes basic fields such as API version, kind, and metadata.
+type MyTestPod struct {
+	APIVersion string `json:"apiVersion"`
+	Kind       string `json:"kind"`
+	Metadata   struct {
+		Name string `json:"name"`
+	} `json:"metadata"`
+}
+
+// DeepCopyObject creates a deep copy of the MyTestPod instance.
+// This method is part of the runtime.Object interface and ensures that modifications
+// to the copy do not affect the original object.
+func (p *MyTestPod) DeepCopyObject() runtime.Object {
+	return &MyTestPod{
+		APIVersion: p.APIVersion,
+		Kind:       p.Kind,
+		Metadata:   p.Metadata,
+	}
+}
+
+// GetObjectKind returns the schema.ObjectKind for the MyTestPod instance.
+// This method is part of the runtime.Object interface and provides the API version
+// and kind of the object, which is used for object identification in Kubernetes.
+func (p *MyTestPod) GetObjectKind() schema.ObjectKind {
+	return &metav1.TypeMeta{
+		APIVersion: p.APIVersion,
+		Kind:       p.Kind,
+	}
+}
+
+// GetAPIVersion returns the API version of the MyTestPod.
+func (p *MyTestPod) GetAPIVersion() string {
+	return p.APIVersion
+}
+
+// GetKind returns the kind of the MyTestPod.
+func (p *MyTestPod) GetKind() string {
+	return p.Kind
+}
+
+// GetName returns the name of the MyTestPod.
+func (p *MyTestPod) GetName() string {
+	return p.Metadata.Name
+}
+
+func TestNewDecoder(t *testing.T) {
+	tests := []struct {
+		name string
+	}{
+		{
+			name: "NewDecoder_ValidDecoder_DecoderIsValid",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			scheme := runtime.NewScheme()
+			decoder := NewDecoder(scheme)
+			if decoder == nil {
+				t.Errorf("expected decoder to not be nil")
+			}
+		})
+	}
+}
+
+func TestDecodeRaw(t *testing.T) {
+	tests := []struct {
+		name       string
+		apiVersion string
+		kind       string
+		objName    string
+		rawObj     *runtime.RawExtension
+		into       Interface
+		prep       func(re *runtime.RawExtension, apiVersion, kind, name string) error
+		verify     func(into Interface, apiVersion, kind, name string) error
+		wantErr    bool
+		errMsg     string
+	}{
+		{
+			name:       "DecodeRaw_ValidRaw_DecodeRawIsSuccessful",
+			objName:    "test-pod",
+			kind:       "Pod",
+			apiVersion: "v1",
+			rawObj: &runtime.RawExtension{
+				Raw: []byte{},
+			},
+			into: &unstructured.Unstructured{},
+			prep: func(re *runtime.RawExtension, apiVersion, kind, name string) error {
+				re.Raw = []byte(fmt.Sprintf(`{"apiVersion": "%s", "kind": "%s", "metadata": {"name": "%s"}}`, apiVersion, kind, name))
+				return nil
+			},
+			verify:  verifyRuntimeObject,
+			wantErr: false,
+		},
+		{
+			name:       "DecodeRaw_IntoNonUnstructuredType_RawDecoded",
+			objName:    "test-pod",
+			kind:       "Pod",
+			apiVersion: "v1",
+			rawObj: &runtime.RawExtension{
+				Raw: []byte{},
+			},
+			into: &MyTestPod{},
+			prep: func(re *runtime.RawExtension, apiVersion, kind, name string) error {
+				re.Raw = []byte(fmt.Sprintf(`{"apiVersion": "%s", "kind": "%s", "metadata": {"name": "%s"}}`, apiVersion, kind, name))
+				return nil
+			},
+			verify:  verifyRuntimeObject,
+			wantErr: false,
+		},
+		{
+			name: "DecodeRaw_EmptyRaw_NoContentToDecode",
+			rawObj: &runtime.RawExtension{
+				Raw: []byte{},
+			},
+			into:    &unstructured.Unstructured{},
+			prep:    func(*runtime.RawExtension, string, string, string) error { return nil },
+			verify:  func(Interface, string, string, string) error { return nil },
+			wantErr: true,
+			errMsg:  "there is no content to decode",
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if err := test.prep(test.rawObj, test.apiVersion, test.kind, test.objName); err != nil {
+				t.Errorf("failed to prep the runtime raw extension object: %v", err)
+			}
+			scheme := runtime.NewScheme()
+			decoder := NewDecoder(scheme)
+			intoObj, ok := test.into.(runtime.Object)
+			if !ok {
+				t.Errorf("failed to type assert into object into runtime rawextension")
+			}
+			err := decoder.DecodeRaw(*test.rawObj, intoObj)
+			if err != nil && !test.wantErr {
+				t.Errorf("unexpected error while decoding the raw: %v", err)
+			}
+			if err == nil && test.wantErr {
+				t.Errorf("expected an error, but got none")
+			}
+			if err != nil && test.wantErr && !strings.Contains(err.Error(), test.errMsg) {
+				t.Errorf("expected %s error msg to contain %s", err.Error(), test.errMsg)
+			}
+			if err := test.verify(test.into, test.apiVersion, test.kind, test.objName); err != nil {
+				t.Errorf("failed to verify decoding the raw: %v", err)
+			}
+		})
+	}
+}
+
+func TestDecode(t *testing.T) {
+	tests := []struct {
+		name       string
+		apiVersion string
+		kind       string
+		objName    string
+		req        *Request
+		into       Interface
+		prep       func(re *Request, apiVersion, kind, name string) error
+		verify     func(into Interface, apiVersion, kind, name string) error
+		wantErr    bool
+		errMsg     string
+	}{
+		{
+			name:       "Decode_ValidRequest_DecodeRequestIsSuccessful",
+			objName:    "test-pod",
+			kind:       "Pod",
+			apiVersion: "v1",
+			req: &Request{
+				ResourceInterpreterRequest: configv1alpha1.ResourceInterpreterRequest{
+					Object: runtime.RawExtension{},
+				},
+			},
+			into: &unstructured.Unstructured{},
+			prep: func(re *Request, apiVersion, kind, name string) error {
+				re.ResourceInterpreterRequest.Object.Raw = []byte(fmt.Sprintf(`{"apiVersion": "%s", "kind": "%s", "metadata": {"name": "%s"}}`, apiVersion, kind, name))
+				return nil
+			},
+			verify:  verifyRuntimeObject,
+			wantErr: false,
+		},
+		{
+			name: "Decode_EmptyRaw_NoContentToDecode",
+			req: &Request{
+				ResourceInterpreterRequest: configv1alpha1.ResourceInterpreterRequest{
+					Object: runtime.RawExtension{},
+				},
+			},
+			into:    &unstructured.Unstructured{},
+			prep:    func(*Request, string, string, string) error { return nil },
+			verify:  func(Interface, string, string, string) error { return nil },
+			wantErr: true,
+			errMsg:  "there is no content to decode",
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if err := test.prep(test.req, test.apiVersion, test.kind, test.objName); err != nil {
+				t.Errorf("failed to prep the runtime raw extension object: %v", err)
+			}
+			scheme := runtime.NewScheme()
+			decoder := NewDecoder(scheme)
+			if decoder == nil {
+				t.Errorf("expected decoder to not be nil")
+			}
+			intoObj, ok := test.into.(runtime.Object)
+			if !ok {
+				t.Errorf("failed to type assert into object into runtime rawextension")
+			}
+			err := decoder.Decode(*test.req, intoObj)
+			if err != nil && !test.wantErr {
+				t.Errorf("unexpected error while decoding the raw: %v", err)
+			}
+			if err == nil && test.wantErr {
+				t.Errorf("expected an error, but got none")
+			}
+			if err != nil && test.wantErr && !strings.Contains(err.Error(), test.errMsg) {
+				t.Errorf("expected %s error msg to contain %s", err.Error(), test.errMsg)
+			}
+			if err := test.verify(test.into, test.apiVersion, test.kind, test.objName); err != nil {
+				t.Errorf("failed to verify decoding the raw: %v", err)
+			}
+		})
+	}
+}
+
+// verifyRuntimeObject checks if the runtime object (`into`) matches the given
+// `apiVersion`, `kind`, and `name`. It returns an error if any field doesn't match.
+func verifyRuntimeObject(into Interface, apiVersion, kind, name string) error {
+	if got := into.GetAPIVersion(); got != apiVersion {
+		return fmt.Errorf("expected API version '%s', got '%s'", apiVersion, got)
+	}
+	if got := into.GetKind(); got != kind {
+		return fmt.Errorf("expected kind '%s', got '%s'", kind, got)
+	}
+	if got := into.GetName(); got != name {
+		return fmt.Errorf("expected name '%s', got '%s'", name, got)
+	}
+	return nil
+}