Files
opentimestamps/varn/varn_test.go
2025-04-11 13:31:02 +02:00

119 lines
2.8 KiB
Go

package varn_test
import (
"bytes"
"encoding/hex"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"git.intruders.space/public/opentimestamps/varn"
)
// Helper functions for decoding (to verify encoding)
func readVarUint(t *testing.T, data []byte) (uint64, int) {
t.Helper()
require.NotZero(t, data, "empty buffer")
if data[0] == 0 {
return 0, 1
}
var value uint64
var bytesRead int
for i, b := range data {
bytesRead = i + 1
value |= uint64(b&0x7F) << uint(7*i)
if b&0x80 == 0 {
break
}
require.Less(t, i, 9, "varint too long") // 9 is max bytes needed for uint64
}
return value, bytesRead
}
func readVarBytes(t *testing.T, data []byte) ([]byte, int) {
t.Helper()
length, bytesRead := readVarUint(t, data)
require.GreaterOrEqual(t, uint64(len(data)-bytesRead), length, "buffer too short")
end := bytesRead + int(length)
return data[bytesRead:end], end
}
func TestAppendVarUint(t *testing.T) {
tests := []struct {
name string
value uint64
expected string // hex representation of expected bytes
}{
{"zero", 0, "00"},
{"small value", 42, "2a"},
{"value below 128", 127, "7f"},
{"value requiring 2 bytes", 128, "8001"},
{"medium value", 300, "ac02"},
{"large value", 1234567890, "d285d8cc04"}, // Updated from "d2a6e58e07" to correct encoding
{"max uint64", 18446744073709551615, "ffffffffffffffffff01"},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
var buf []byte
result := varn.AppendVarUint(buf, tt.value)
// Check encoding
expected, err := hex.DecodeString(tt.expected)
assert.NoError(t, err)
assert.Equal(t, expected, result)
// Verify by decoding
decoded, _ := readVarUint(t, result)
assert.Equal(t, tt.value, decoded)
})
}
}
func TestAppendVarBytes(t *testing.T) {
tests := []struct {
name string
value []byte
}{
{"empty", []byte{}},
{"small", []byte{0x01, 0x02, 0x03}},
{"medium", bytes.Repeat([]byte{0xAA}, 127)},
{"large", bytes.Repeat([]byte{0xBB}, 256)},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
var buf []byte
result := varn.AppendVarBytes(buf, tt.value)
// Verify by decoding
decoded, _ := readVarBytes(t, result)
assert.Equal(t, tt.value, decoded)
// Check that length is properly encoded
lenEncoded, _ := readVarUint(t, result)
assert.Equal(t, uint64(len(tt.value)), lenEncoded)
})
}
}
func TestAppendingToExistingBuffer(t *testing.T) {
existing := []byte{0xFF, 0xFF}
// Test AppendVarUint
result := varn.AppendVarUint(existing, 42)
assert.Equal(t, []byte{0xFF, 0xFF, 0x2A}, result)
// Test AppendVarBytes
data := []byte{0x01, 0x02, 0x03}
result = varn.AppendVarBytes(existing, data)
assert.Equal(t, []byte{0xFF, 0xFF, 0x03, 0x01, 0x02, 0x03}, result)
}