Files
2026-07-13 13:00:08 +08:00

320 lines
8.0 KiB
Go

package encoding
import (
"bytes"
"encoding/binary"
"os"
"path/filepath"
"strings"
"testing"
"unicode/utf16"
"golang.org/x/text/encoding/simplifiedchinese"
)
// --- Detect ---
func TestDetectUTF8Plain(t *testing.T) {
enc, _ := Detect([]byte("hello world\n"))
if enc != UTF8 {
t.Errorf("got %v, want UTF8", enc)
}
}
func TestDetectUTF8BOM(t *testing.T) {
in := append([]byte{0xEF, 0xBB, 0xBF}, []byte("hello")...)
enc, _ := Detect(in)
if enc != UTF8BOM {
t.Errorf("got %v, want UTF8BOM", enc)
}
}
func TestDetectUTF16LE(t *testing.T) {
var b bytes.Buffer
b.Write([]byte{0xFF, 0xFE})
for _, r := range utf16.Encode([]rune("hello")) {
_ = binary.Write(&b, binary.LittleEndian, r)
}
enc, _ := Detect(b.Bytes())
if enc != UTF16LE {
t.Errorf("got %v, want UTF16LE", enc)
}
}
func TestDetectUTF16BE(t *testing.T) {
var b bytes.Buffer
b.Write([]byte{0xFE, 0xFF})
for _, r := range utf16.Encode([]rune("hello")) {
_ = binary.Write(&b, binary.BigEndian, r)
}
enc, _ := Detect(b.Bytes())
if enc != UTF16BE {
t.Errorf("got %v, want UTF16BE", enc)
}
}
func TestDetectGB18030(t *testing.T) {
gb, err := simplifiedchinese.GB18030.NewEncoder().String("你好世界")
if err != nil {
t.Fatalf("encode: %v", err)
}
enc, _ := Detect([]byte(gb))
if enc != GB18030 {
t.Errorf("got %v, want GB18030", enc)
}
}
func TestDetectEmpty(t *testing.T) {
enc, _ := Detect(nil)
if enc != UTF8 {
t.Errorf("empty input: got %v, want UTF8", enc)
}
}
// --- Decode ---
func TestDecodeUTF8(t *testing.T) {
in := []byte("hello\n世界")
out := Decode(in, UTF8)
if string(out) != "hello\n世界" {
t.Errorf("got %q", out)
}
}
func TestReadFileUTF8DecodesGB18030(t *testing.T) {
path := filepath.Join(t.TempDir(), "settings.json")
if err := os.WriteFile(path, Encode(`{"label":"中文"}`, GB18030), 0o644); err != nil {
t.Fatal(err)
}
got, err := ReadFileUTF8(path)
if err != nil {
t.Fatal(err)
}
if string(got) != `{"label":"中文"}` {
t.Fatalf("ReadFileUTF8 = %q", got)
}
}
func TestDecodeUTF8BOM(t *testing.T) {
in := append([]byte{0xEF, 0xBB, 0xBF}, []byte("hello")...)
out := Decode(in, UTF8BOM)
if string(out) != "hello" {
t.Errorf("got %q, want 'hello'", out)
}
if bytes.Contains(out, []byte{0xEF, 0xBB, 0xBF}) {
t.Error("BOM leaked into decoded output")
}
}
func TestDecodeUTF16LE(t *testing.T) {
var b bytes.Buffer
b.Write([]byte{0xFF, 0xFE})
for _, r := range utf16.Encode([]rune("hello\nworld")) {
_ = binary.Write(&b, binary.LittleEndian, r)
}
out := Decode(b.Bytes(), UTF16LE)
if string(out) != "hello\nworld" {
t.Errorf("got %q", out)
}
}
func TestDecodeUTF16BE(t *testing.T) {
var b bytes.Buffer
b.Write([]byte{0xFE, 0xFF})
for _, r := range utf16.Encode([]rune("hello\nworld")) {
_ = binary.Write(&b, binary.BigEndian, r)
}
out := Decode(b.Bytes(), UTF16BE)
if string(out) != "hello\nworld" {
t.Errorf("got %q", out)
}
}
func TestDecodeGB18030(t *testing.T) {
gb, _ := simplifiedchinese.GB18030.NewEncoder().String("你好世界\n第二行")
out := Decode([]byte(gb), GB18030)
if string(out) != "你好世界\n第二行" {
t.Errorf("got %q", out)
}
}
func TestDecodeLossyUTF8(t *testing.T) {
in := []byte{0xFF, 0xFE, 'a'}
out := Decode(in, LossyUTF8)
if !bytes.Equal(out, in) {
t.Errorf("LossyUTF8 should pass through, got %q", out)
}
}
// --- Encode ---
func TestEncodeUTF8(t *testing.T) {
out := Encode("hello", UTF8)
if string(out) != "hello" {
t.Errorf("got %q", out)
}
}
func TestEncodeUTF8BOM(t *testing.T) {
out := Encode("hello", UTF8BOM)
if !bytes.HasPrefix(out, []byte{0xEF, 0xBB, 0xBF}) {
t.Error("missing UTF-8 BOM prefix")
}
if string(out[3:]) != "hello" {
t.Errorf("body = %q", out[3:])
}
}
func TestEncodeUTF16LE(t *testing.T) {
out := Encode("hi", UTF16LE)
if len(out) < 2 || out[0] != 0xFF || out[1] != 0xFE {
t.Error("missing UTF-16LE BOM")
}
decoded := Decode(out, UTF16LE)
if string(decoded) != "hi" {
t.Errorf("round-trip failed: got %q", decoded)
}
}
func TestEncodeUTF16BE(t *testing.T) {
out := Encode("hi", UTF16BE)
if len(out) < 2 || out[0] != 0xFE || out[1] != 0xFF {
t.Error("missing UTF-16BE BOM")
}
decoded := Decode(out, UTF16BE)
if string(decoded) != "hi" {
t.Errorf("round-trip failed: got %q", decoded)
}
}
func TestEncodeGB18030(t *testing.T) {
out := Encode("你好", GB18030)
dec, _ := simplifiedchinese.GB18030.NewDecoder().Bytes(out)
if string(dec) != "你好" {
t.Errorf("round-trip failed: got %q", dec)
}
}
// --- Round-trip ---
func TestRoundTripGB18030(t *testing.T) {
original := "你好世界\n第二行\n"
gb, _ := simplifiedchinese.GB18030.NewEncoder().String(original)
enc, _ := Detect([]byte(gb))
decoded := string(Decode([]byte(gb), enc))
if decoded != original {
t.Fatalf("decode mismatch: %q", decoded)
}
edited := strings.Replace(decoded, "第二行", "新的行", 1)
reencoded := Encode(edited, enc)
redecoded := string(Decode(reencoded, enc))
if redecoded != edited {
t.Errorf("round-trip failed: got %q, want %q", redecoded, edited)
}
}
func TestRoundTripUTF16LE(t *testing.T) {
original := "hello\nworld\n"
encoded := Encode(original, UTF16LE)
enc, _ := Detect(encoded)
decoded := string(Decode(encoded, enc))
if decoded != original {
t.Errorf("round-trip failed: got %q, want %q", decoded, original)
}
}
func TestRoundTripUTF8BOM(t *testing.T) {
original := "hello world\n"
encoded := Encode(original, UTF8BOM)
enc, _ := Detect(encoded)
decoded := string(Decode(encoded, enc))
if decoded != original {
t.Errorf("round-trip failed: got %q, want %q", decoded, original)
}
}
// --- BOM-less UTF-16 ---
func utf16NoBOM(t *testing.T, s string, order binary.ByteOrder) []byte {
t.Helper()
var b bytes.Buffer
for _, r := range utf16.Encode([]rune(s)) {
_ = binary.Write(&b, order, r)
}
return b.Bytes()
}
func TestDetectUTF16LENoBOM(t *testing.T) {
in := utf16NoBOM(t, "// Created by 69431 on 2024/12/31\n#include \"x.h\"\n", binary.LittleEndian)
enc, _ := Detect(in)
if enc != UTF16LENoBOM {
t.Errorf("got %v, want UTF16LENoBOM", enc)
}
}
func TestDetectUTF16BENoBOM(t *testing.T) {
in := utf16NoBOM(t, "package main\nfunc main() {}\n", binary.BigEndian)
enc, _ := Detect(in)
if enc != UTF16BENoBOM {
t.Errorf("got %v, want UTF16BENoBOM", enc)
}
}
func TestDetectPlainUTF8NotUTF16(t *testing.T) {
enc, _ := Detect([]byte("the quick brown fox jumps over the lazy dog\n"))
if enc != UTF8 {
t.Errorf("ASCII text misdetected as %v", enc)
}
}
func TestDetectBinaryNotUTF16NoBOM(t *testing.T) {
// NULs on both parities — genuine binary must not look like BOM-less UTF-16.
bin := []byte{0x00, 0x00, 0x01, 0x00, 0x00, 0x02, 0xFF, 0x00, 0x00, 0x03, 0x00, 0x00, 0x04, 0x00, 0x00, 0x05, 0x00, 0x00}
if k, ok := DetectUTF16NoBOM(bin); ok {
t.Errorf("binary misdetected as %v", k)
}
}
func TestDecodeUTF16LENoBOM(t *testing.T) {
in := utf16NoBOM(t, "hello\nworld", binary.LittleEndian)
if out := string(Decode(in, UTF16LENoBOM)); out != "hello\nworld" {
t.Errorf("got %q", out)
}
}
func TestRoundTripUTF16LENoBOM(t *testing.T) {
original := "// c++ source\nint main() { return 0; }\n"
encoded := utf16NoBOM(t, original, binary.LittleEndian)
enc, _ := Detect(encoded)
if enc != UTF16LENoBOM {
t.Fatalf("detect: got %v", enc)
}
decoded := string(Decode(encoded, enc))
if decoded != original {
t.Fatalf("decode mismatch: %q", decoded)
}
edited := strings.Replace(decoded, "return 0", "return 1", 1)
reencoded := Encode(edited, enc)
if bytes.HasPrefix(reencoded, []byte{0xFF, 0xFE}) || bytes.HasPrefix(reencoded, []byte{0xFE, 0xFF}) {
t.Error("no-BOM re-encode leaked a BOM")
}
if redecoded := string(Decode(reencoded, enc)); redecoded != edited {
t.Errorf("round-trip failed: got %q, want %q", redecoded, edited)
}
}
// --- UTF-16 supplementary plane (surrogate pairs) ---
func TestSurrogatePairRoundTrip(t *testing.T) {
// U+1F600 (😀) is in the supplementary plane and requires a surrogate pair.
original := "hello 😀 world"
encoded := Encode(original, UTF16LE)
decoded := string(Decode(encoded, UTF16LE))
if decoded != original {
t.Errorf("surrogate pair round-trip failed: got %q, want %q", decoded, original)
}
}