fix tests

Author: noboruma

conn.go

@@ -775,6 +775,11 @@ func (c *Conn) fragmentHandshake(dtlsHandshake *handshake.Handshake) ([][]byte,
 	}
 
 	contentFragments := splitBytes(content, c.maximumTransmissionUnit)
+	if len(contentFragments) == 0 {
+		contentFragments = [][]byte{
+			{},
+		}
+	}
 
 	offset := 0
 	fragmentedHandshakes := make([][]byte, 0, len(contentFragments))

pkg/protocol/handshake/message_certificate_13.go

@@ -85,17 +85,19 @@ func (m *MessageCertificate13) Size() int {
 
 func (m *MessageCertificate13) cacheMarshalExtensions() error {
 	if m.marchalledExtensions == nil && m.marchalledExtensionsErr == nil {
-		for _, entry := range m.CertificateList {
+		m.marchalledExtensions = make([][]byte, len(m.CertificateList))
+		for i, entry := range m.CertificateList {
 			for _, ext := range entry.Extensions {
 				var c []byte
 				c, m.marchalledExtensionsErr = ext.Marshal()
 				if m.marchalledExtensionsErr != nil {
 					return m.marchalledExtensionsErr
 				}
-				m.marchalledExtensions = append(m.marchalledExtensions, c)
+				m.marchalledExtensions[i] = append(m.marchalledExtensions[i], c...)
 			}
 		}
 	}
+
 	return m.marchalledExtensionsErr
 }
 

pkg/protocol/handshake/message_client_hello.go

@@ -42,6 +42,7 @@ func (m *MessageClientHello) cacheMarshalExtensions() error {
 	if m.marchalledExtensions == nil && m.marchalledExtensionsErr == nil {
 		m.marchalledExtensions, m.marchalledExtensionsErr = extension.Marshal(m.Extensions)
 	}
+
 	return m.marchalledExtensionsErr
 }
 

pkg/protocol/handshake/message_client_key_exchange.go

@@ -52,6 +52,7 @@ func (m *MessageClientKeyExchange) Size() int {
 	total := 0
 	if m.IdentityHint != nil {
 		total += 2
+		total += len(m.IdentityHint)
 	}
 
 	if m.PublicKey != nil {

pkg/protocol/handshake/message_server_hello.go

@@ -40,12 +40,12 @@ func (m *MessageServerHello) cacheMarshalExtensions() error {
 	if m.marchalledExtensions == nil && m.marchalledExtensionsErr == nil {
 		m.marchalledExtensions, m.marchalledExtensionsErr = extension.Marshal(m.Extensions)
 	}
+
 	return m.marchalledExtensionsErr
 }
 
 // Size returns the size required by MarshalInto.
 func (m *MessageServerHello) Size() int {
-
 	err := m.cacheMarshalExtensions()
 	if err != nil {
 		return 0
@@ -60,7 +60,6 @@ func (m *MessageServerHello) Size() int {
 
 // MarshalInto encodes the Handshake into a pre-allocated buffer.
 func (m *MessageServerHello) MarshalInto(out []byte) error {
-
 	err := m.cacheMarshalExtensions()
 	if err != nil {
 		return err