refactor: 重构trustlog-sdk目录结构到trustlog/go-trustlog

- 将所有trustlog-sdk文件移动到trustlog/go-trustlog/目录
- 更新README中所有import路径从trustlog-sdk改为go-trustlog
- 更新cookiecutter配置文件中的项目名称
- 更新根目录.lefthook.yml以引用新位置的配置
- 添加go.sum文件到版本控制
- 删除过时的示例文件

这次重构与trustlog-server保持一致的目录结构，
为未来支持多语言SDK（Python、Java等）预留空间。

internal/helpers/tlv_test.go

@@ -0,0 +1,267 @@
+package helpers_test
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"go.yandata.net/iod/iod/trustlog-sdk/internal/helpers"
+)
+
+func TestNewTLVReader(t *testing.T) {
+	t.Parallel()
+
+	r := bytes.NewReader([]byte{})
+	reader := helpers.NewTLVReader(r)
+	assert.NotNil(t, reader)
+}
+
+func TestNewTLVWriter(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	writer := helpers.NewTLVWriter(&buf)
+	assert.NotNil(t, writer)
+}
+
+func TestTLVWriter_WriteField(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name    string
+		value   []byte
+		wantErr bool
+	}{
+		{
+			name:    "normal field",
+			value:   []byte("test"),
+			wantErr: false,
+		},
+		{
+			name:    "empty field",
+			value:   []byte{},
+			wantErr: false,
+		},
+		{
+			name:    "large field",
+			value:   make([]byte, 1000),
+			wantErr: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			var buf bytes.Buffer
+			writer := helpers.NewTLVWriter(&buf)
+			err := writer.WriteField(tt.value)
+			if tt.wantErr {
+				require.Error(t, err)
+			} else {
+				require.NoError(t, err)
+				if len(tt.value) > 0 {
+					assert.Positive(t, buf.Len())
+				}
+			}
+		})
+	}
+}
+
+func TestTLVWriter_WriteStringField(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	writer := helpers.NewTLVWriter(&buf)
+
+	err := writer.WriteStringField("test")
+	require.NoError(t, err)
+	assert.Positive(t, buf.Len())
+}
+
+func TestTLVReader_ReadField(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name    string
+		setup   func() *helpers.TLVReader
+		wantErr bool
+	}{
+		{
+			name: "normal field",
+			setup: func() *helpers.TLVReader {
+				var buf bytes.Buffer
+				writer := helpers.NewTLVWriter(&buf)
+				_ = writer.WriteField([]byte("test"))
+				return helpers.NewTLVReader(&buf)
+			},
+			wantErr: false,
+		},
+		{
+			name: "empty field",
+			setup: func() *helpers.TLVReader {
+				var buf bytes.Buffer
+				writer := helpers.NewTLVWriter(&buf)
+				_ = writer.WriteField([]byte{})
+				return helpers.NewTLVReader(&buf)
+			},
+			wantErr: false,
+		},
+		{
+			name: "invalid data",
+			setup: func() *helpers.TLVReader {
+				return helpers.NewTLVReader(bytes.NewReader([]byte{0xff, 0xff}))
+			},
+			wantErr: true,
+		},
+		{
+			name: "empty reader",
+			setup: func() *helpers.TLVReader {
+				return helpers.NewTLVReader(bytes.NewReader([]byte{}))
+			},
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+			reader := tt.setup()
+			result, err := reader.ReadField()
+			if tt.wantErr {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				// Empty field returns nil
+				if tt.name == "empty field" {
+					assert.Nil(t, result)
+				} else {
+					assert.NotNil(t, result)
+				}
+			}
+		})
+	}
+}
+
+func TestTLVReader_ReadStringField(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	writer := helpers.NewTLVWriter(&buf)
+	err := writer.WriteStringField("test")
+	require.NoError(t, err)
+
+	reader := helpers.NewTLVReader(&buf)
+	result, err := reader.ReadStringField()
+	require.NoError(t, err)
+	assert.Equal(t, "test", result)
+}
+
+func TestTLV_RoundTrip(t *testing.T) {
+	t.Parallel()
+
+	tests := []struct {
+		name  string
+		value []byte
+	}{
+		{
+			name:  "normal",
+			value: []byte("test"),
+		},
+		{
+			name:  "empty",
+			value: []byte{},
+		},
+		{
+			name:  "large",
+			value: make([]byte, 100),
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
+
+			// Write
+			var buf bytes.Buffer
+			writer := helpers.NewTLVWriter(&buf)
+			err := writer.WriteField(tt.value)
+			require.NoError(t, err)
+
+			// Read
+			reader := helpers.NewTLVReader(&buf)
+			result, err := reader.ReadField()
+			require.NoError(t, err)
+
+			// Verify
+			// Empty byte slice returns nil from ReadField
+			if len(tt.value) == 0 {
+				assert.Nil(t, result)
+			} else {
+				assert.Equal(t, tt.value, result)
+			}
+		})
+	}
+}
+
+func TestTLV_MultipleFields(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	writer := helpers.NewTLVWriter(&buf)
+
+	// Write multiple fields
+	fields := [][]byte{
+		[]byte("field1"),
+		[]byte("field2"),
+		[]byte("field3"),
+	}
+
+	for _, field := range fields {
+		err := writer.WriteField(field)
+		require.NoError(t, err)
+	}
+
+	// Read multiple fields
+	reader := helpers.NewTLVReader(&buf)
+	for i, expected := range fields {
+		result, err := reader.ReadField()
+		require.NoError(t, err, "field %d", i)
+		assert.Equal(t, expected, result, "field %d", i)
+	}
+}
+
+func TestTLV_StringRoundTrip(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	writer := helpers.NewTLVWriter(&buf)
+
+	original := "test string"
+	err := writer.WriteStringField(original)
+	require.NoError(t, err)
+
+	reader := helpers.NewTLVReader(&buf)
+	result, err := reader.ReadStringField()
+	require.NoError(t, err)
+	assert.Equal(t, original, result)
+}
+
+func TestTLVReader_ReadField_EOF(t *testing.T) {
+	t.Parallel()
+
+	var buf bytes.Buffer
+	writer := helpers.NewTLVWriter(&buf)
+	_ = writer.WriteField([]byte("test"))
+
+	reader := helpers.NewTLVReader(&buf)
+	_, err := reader.ReadField()
+	require.NoError(t, err)
+
+	// Try to read beyond EOF - this will fail when trying to read varint length
+	_, err = reader.ReadField()
+	require.Error(t, err)
+	// Error could be EOF or other read error
+	assert.Contains(t, err.Error(), "failed to read")
+}