refactor

varn/buffer_test.go

@@ -0,0 +1,155 @@
+package varn_test
+
+import (
+	"io"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+
+	"git.intruders.space/public/opentimestamps/varn"
+)
+
+func TestNewBuffer(t *testing.T) {
+	data := []byte{0x01, 0x02, 0x03}
+	buf := varn.NewBuffer(data)
+
+	// Test the first byte to verify initialization
+	b, err := buf.ReadByte()
+	assert.NoError(t, err)
+	assert.Equal(t, byte(0x01), b)
+
+	// Test reading the second byte
+	b, err = buf.ReadByte()
+	assert.NoError(t, err)
+	assert.Equal(t, byte(0x02), b)
+
+	// Test reading the third byte
+	b, err = buf.ReadByte()
+	assert.NoError(t, err)
+	assert.Equal(t, byte(0x03), b)
+
+	// Test reading beyond the buffer
+	_, err = buf.ReadByte()
+	assert.ErrorIs(t, err, io.EOF)
+
+	// Test reading from an empty buffer
+	emptyBuf := varn.NewBuffer([]byte{})
+	_, err = emptyBuf.ReadByte()
+	assert.ErrorIs(t, err, io.EOF)
+
+	// Test reading from a nil buffer
+	nilBuf := varn.NewBuffer(nil)
+	_, err = nilBuf.ReadByte()
+	assert.ErrorIs(t, err, io.EOF)
+
+	// Test reading from a buffer with a single byte
+	singleByteBuf := varn.NewBuffer([]byte{0xFF})
+	b, err = singleByteBuf.ReadByte()
+	assert.NoError(t, err)
+	assert.Equal(t, byte(0xFF), b)
+}
+
+func TestReadBytes(t *testing.T) {
+	data := []byte{0x01, 0x02, 0x03, 0x04, 0x05}
+	buf := varn.NewBuffer(data)
+
+	// Read 3 bytes
+	bytes, err := buf.ReadBytes(3)
+	assert.NoError(t, err)
+	assert.Equal(t, []byte{0x01, 0x02, 0x03}, bytes)
+
+	// Read 2 more bytes
+	bytes, err = buf.ReadBytes(2)
+	assert.NoError(t, err)
+	assert.Equal(t, []byte{0x04, 0x05}, bytes)
+
+	// Try to read beyond the buffer
+	_, err = buf.ReadBytes(1)
+	assert.ErrorIs(t, err, io.EOF)
+}
+
+func TestReadByte(t *testing.T) {
+	data := []byte{0x0A, 0x0B}
+	buf := varn.NewBuffer(data)
+
+	// Read first byte
+	b, err := buf.ReadByte()
+	assert.NoError(t, err)
+	assert.Equal(t, byte(0x0A), b)
+
+	// Read second byte
+	b, err = buf.ReadByte()
+	assert.NoError(t, err)
+	assert.Equal(t, byte(0x0B), b)
+
+	// Try to read beyond the buffer
+	_, err = buf.ReadByte()
+	assert.ErrorIs(t, err, io.EOF)
+}
+
+func TestReadVarUint(t *testing.T) {
+	testCases := []struct {
+		name     string
+		input    []byte
+		expected uint64
+	}{
+		{
+			name:     "Single byte",
+			input:    []byte{0x01},
+			expected: 1,
+		},
+		{
+			name:     "Two bytes",
+			input:    []byte{0x81, 0x01}, // 129 in varint encoding
+			expected: 129,
+		},
+		{
+			name:     "Large number",
+			input:    []byte{0xFF, 0xFF, 0xFF, 0xFF, 0x01}, // 536870911 in varint encoding
+			expected: 536870911,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			buf := varn.NewBuffer(tc.input)
+			val, err := buf.ReadVarUint()
+			assert.NoError(t, err)
+			assert.Equal(t, tc.expected, val)
+		})
+	}
+
+	// Test EOF
+	buf := varn.NewBuffer([]byte{0x81}) // Incomplete varint
+	_, err := buf.ReadVarUint()
+	assert.ErrorIs(t, err, io.EOF)
+}
+
+func TestReadVarBytes(t *testing.T) {
+	// Test normal case: length followed by data
+	data := []byte{0x03, 0x0A, 0x0B, 0x0C, 0x0D}
+	buf := varn.NewBuffer(data)
+
+	bytes, err := buf.ReadVarBytes()
+	assert.NoError(t, err)
+	assert.Equal(t, []byte{0x0A, 0x0B, 0x0C}, bytes)
+
+	// Test empty array
+	data = []byte{0x00, 0x01}
+	buf = varn.NewBuffer(data)
+
+	bytes, err = buf.ReadVarBytes()
+	assert.NoError(t, err)
+	assert.Equal(t, []byte{}, bytes)
+
+	// Test EOF during length read
+	buf = varn.NewBuffer([]byte{})
+	_, err = buf.ReadVarBytes()
+	assert.ErrorIs(t, err, io.EOF)
+
+	// Test error during data read (insufficient bytes)
+	data = []byte{0x03, 0x01}
+	buf = varn.NewBuffer(data)
+	_, err = buf.ReadVarBytes()
+	assert.ErrorIs(t, err, io.ErrUnexpectedEOF)
+}