test: add unit test

Signed-off-by: Junjie Gao <[email protected]>

internal/crypto/cms/encoding/ber/ber.go

@@ -32,7 +32,7 @@ import (
 // value is the interface for an ASN.1 value node.
 type value interface {
 	// EncodeMetadata encodes the identifier and length in DER to the buffer.
-	EncodeMetadata(*bytes.Buffer) error
+	EncodeMetadata(Writer) error
 
 	// EncodedLen returns the length in bytes of the data when encoding in DER.
 	EncodedLen() int

internal/crypto/cms/encoding/ber/ber_test.go

@@ -300,6 +300,20 @@ func TestConvertToDER(t *testing.T) {
 			der:         []byte{},
 			expectError: true,
 		},
+		{
+			name: "long form length greather than subsequent octets length ",
+			ber: []byte{
+				// Primitive value
+				// identifier
+				0x1f, 0xa0, 0x20,
+				// length
+				0x81, 0x09,
+				// content
+				0x01,
+			},
+			der:         []byte{},
+			expectError: true,
+		},
 	}
 
 	for _, tt := range testData {
@@ -317,3 +331,21 @@ func TestConvertToDER(t *testing.T) {
 		}
 	}
 }
+
+func TestDecodeIdentifier(t *testing.T) {
+	t.Run("identifier is empty", func(t *testing.T) {
+		_, _, err := decodeIdentifier([]byte{})
+		if err == nil {
+			t.Errorf("decodeIdentifier() error = nil, but expect error")
+		}
+	})
+}
+
+func TestDecodeLength(t *testing.T) {
+	t.Run("length is empty", func(t *testing.T) {
+		_, _, err := decodeLength([]byte{})
+		if err == nil {
+			t.Errorf("decodeLength() error = nil, but expect error")
+		}
+	})
+}

internal/crypto/cms/encoding/ber/common.go

@@ -17,6 +17,12 @@ import (
 	"io"
 )
 
+// Writer is the interface that wraps the basic Write and WriteByte methods.
+type Writer interface {
+	io.Writer
+	io.ByteWriter
+}
+
 // encodeLength encodes length octets in DER.
 // Reference: ISO/IEC 8825-1: 10.1
 func encodeLength(w io.ByteWriter, length int) error {

internal/crypto/cms/encoding/ber/constructed.go

@@ -13,8 +13,6 @@
 
 package ber
 
-import "bytes"
-
 // constructed represents a value in constructed.
 type constructed struct {
 	identifier []byte
@@ -25,7 +23,7 @@ type constructed struct {
 
 // EncodeMetadata encodes the identifier and length octets of constructed
 // to the value writer in DER.
-func (v *constructed) EncodeMetadata(w *bytes.Buffer) error {
+func (v *constructed) EncodeMetadata(w Writer) error {
 	_, err := w.Write(v.identifier)
 	if err != nil {
 		return err

internal/crypto/cms/encoding/ber/constructed_test.go

@@ -0,0 +1,56 @@
+// Copyright The Notary Project 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 ber
+
+import (
+	"errors"
+	"testing"
+)
+
+type errorWriter struct{}
+
+func (ew *errorWriter) Write(p []byte) (n int, err error) {
+	return 0, errors.New("write error")
+}
+
+func (ew *errorWriter) WriteByte(c byte) error {
+	return errors.New("write error")
+}
+
+func TestConstructedEncodeMetadata(t *testing.T) {
+	tests := []struct {
+		name      string
+		v         constructed
+		wantError bool
+	}{
+		{
+			name: "Error case",
+			v: constructed{
+				identifier: []byte{0x30},
+				length:     5,
+			},
+			wantError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			w := &errorWriter{}
+			err := tt.v.EncodeMetadata(w)
+			if (err != nil) != tt.wantError {
+				t.Errorf("EncodeMetadata() error = %v, wantError %v", err, tt.wantError)
+			}
+		})
+	}
+}

internal/crypto/cms/encoding/ber/primitive.go

@@ -13,8 +13,6 @@
 
 package ber
 
-import "bytes"
-
 // primitive represents a value in primitive encoding.
 type primitive struct {
 	identifier []byte
@@ -23,7 +21,7 @@ type primitive struct {
 
 // EncodeMetadata encodes the identifier and length octets of primitive to
 // the value writer in DER.
-func (v *primitive) EncodeMetadata(w *bytes.Buffer) error {
+func (v *primitive) EncodeMetadata(w Writer) error {
 	_, err := w.Write(v.identifier)
 	if err != nil {
 		return err

internal/crypto/cms/encoding/ber/primitive_test.go

@@ -0,0 +1,44 @@
+// Copyright The Notary Project 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 ber
+
+import (
+	"testing"
+)
+
+func TestPrimitiveEncodeMetadata(t *testing.T) {
+	tests := []struct {
+		name      string
+		v         primitive
+		wantError bool
+	}{
+		{
+			name: "Error case",
+			v: primitive{
+				identifier: []byte{0x30},
+			},
+			wantError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			w := &errorWriter{}
+			err := tt.v.EncodeMetadata(w)
+			if (err != nil) != tt.wantError {
+				t.Errorf("EncodeMetadata() error = %v, wantError %v", err, tt.wantError)
+			}
+		})
+	}
+}