fix: support multiple amqp data fields

Ref: https://github.com/cloudevents/spec/issues/1275
Signed-off-by: Michael Gasch <15986659+embano1@users.noreply.github.com>

protocol/amqp/v2/message.go

@@ -50,8 +50,10 @@ func NewMessage(message *amqp.Message, receiver *amqp.Receiver) *Message {
 	return &Message{AMQP: message, AMQPrcv: receiver, format: fmt, version: vn}
 }
 
-var _ binding.Message = (*Message)(nil)
-var _ binding.MessageMetadataReader = (*Message)(nil)
+var (
+	_ binding.Message               = (*Message)(nil)
+	_ binding.MessageMetadataReader = (*Message)(nil)
+)
 
 func getSpecVersion(message *amqp.Message) spec.Version {
 	if sv, ok := message.ApplicationProperties[specs.PrefixedSpecVersionName()]; ok {
@@ -74,7 +76,8 @@ func (m *Message) ReadEncoding() binding.Encoding {
 
 func (m *Message) ReadStructured(ctx context.Context, encoder binding.StructuredWriter) error {
 	if m.format != nil {
-		return encoder.SetStructuredEvent(ctx, m.format, bytes.NewReader(m.AMQP.GetData()))
+		data := m.getAmqpData()
+		return encoder.SetStructuredEvent(ctx, m.format, bytes.NewReader(data))
 	}
 	return binding.ErrNotStructured
 }
@@ -106,7 +109,7 @@ func (m *Message) ReadBinary(ctx context.Context, encoder binding.BinaryWriter)
 		}
 	}
 
-	data := m.AMQP.GetData()
+	data := m.getAmqpData()
 	if len(data) != 0 { // Some data
 		err = encoder.SetData(bytes.NewBuffer(data))
 		if err != nil {
@@ -137,3 +140,15 @@ func (m *Message) Finish(err error) error {
 	}
 	return m.AMQPrcv.AcceptMessage(context.Background(), m.AMQP)
 }
+
+// fixes: github.com/cloudevents/spec/issues/1275
+func (m *Message) getAmqpData() []byte {
+	var data []byte
+	amqpData := m.AMQP.Data
+
+	// TODO: replace with slices.Concat once go mod bumped to 1.22
+	for idx := range amqpData {
+		data = append(data, amqpData[idx]...)
+	}
+	return data
+}

protocol/amqp/v2/message_test.go

@@ -62,3 +62,58 @@ func TestNewMessage_message_unknown(t *testing.T) {
 	got := NewMessage(message, &rcv)
 	require.Equal(t, binding.EncodingUnknown, got.ReadEncoding())
 }
+
+func TestMessage_getAmqpData(t *testing.T) {
+	tests := []struct {
+		name    string
+		message *amqp.Message
+		want    []byte
+	}{
+		{
+			name:    "nil data",
+			message: amqp.NewMessage(nil),
+			want:    nil,
+		},
+		{
+			name:    "empty string",
+			message: amqp.NewMessage([]byte(`""`)),
+			want:    []byte(`""`),
+		},
+		{
+			name:    "simple string",
+			message: amqp.NewMessage([]byte("hello world")),
+			want:    []byte("hello world"),
+		},
+		{
+			name: "multiple data with simple strings",
+			message: &amqp.Message{Data: [][]byte{
+				[]byte("hello"),
+				[]byte(" "),
+				[]byte("world"),
+			}},
+			want: []byte("hello world"),
+		},
+		{
+			name: "multiple data to build JSON array",
+			message: &amqp.Message{Data: [][]byte{
+				[]byte("["),
+				[]byte("Foo"),
+				[]byte(","),
+				[]byte("Bar"),
+				[]byte(","),
+				[]byte("Baz"),
+				[]byte("]"),
+			}},
+			want: []byte("[Foo,Bar,Baz]"),
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			m := &Message{
+				AMQP: tt.message,
+			}
+			got := m.getAmqpData()
+			require.Equal(t, tt.want, got)
+		})
+	}
+}