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// Copyright 2010 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gzip
import (
"bufio"
"bytes"
"io"
"reflect"
"testing"
"time"
)
// TestEmpty tests that an empty payload still forms a valid GZIP stream.
func TestEmpty(t *testing.T) {
buf := new(bytes.Buffer)
if err := NewWriter(buf).Close(); err != nil {
t.Fatalf("Writer.Close: %v", err)
}
r, err := NewReader(buf)
if err != nil {
t.Fatalf("NewReader: %v", err)
}
if want := (Header{OS: 255}); !reflect.DeepEqual(r.Header, want) {
t.Errorf("Header mismatch:\ngot %#v\nwant %#v", r.Header, want)
}
b, err := io.ReadAll(r)
if err != nil {
t.Fatalf("ReadAll: %v", err)
}
if len(b) != 0 {
t.Fatalf("got %d bytes, want 0", len(b))
}
if err := r.Close(); err != nil {
t.Fatalf("Reader.Close: %v", err)
}
}
// TestRoundTrip tests that gzipping and then gunzipping is the identity
// function.
func TestRoundTrip(t *testing.T) {
buf := new(bytes.Buffer)
w := NewWriter(buf)
w.Comment = "comment"
w.Extra = []byte("extra")
w.ModTime = time.Unix(1e8, 0)
w.Name = "name"
if _, err := w.Write([]byte("payload")); err != nil {
t.Fatalf("Write: %v", err)
}
if err := w.Close(); err != nil {
t.Fatalf("Writer.Close: %v", err)
}
r, err := NewReader(buf)
if err != nil {
t.Fatalf("NewReader: %v", err)
}
b, err := io.ReadAll(r)
if err != nil {
t.Fatalf("ReadAll: %v", err)
}
if string(b) != "payload" {
t.Fatalf("payload is %q, want %q", string(b), "payload")
}
if r.Comment != "comment" {
t.Fatalf("comment is %q, want %q", r.Comment, "comment")
}
if string(r.Extra) != "extra" {
t.Fatalf("extra is %q, want %q", r.Extra, "extra")
}
if r.ModTime.Unix() != 1e8 {
t.Fatalf("mtime is %d, want %d", r.ModTime.Unix(), uint32(1e8))
}
if r.Name != "name" {
t.Fatalf("name is %q, want %q", r.Name, "name")
}
if err := r.Close(); err != nil {
t.Fatalf("Reader.Close: %v", err)
}
}
// TestLatin1 tests the internal functions for converting to and from Latin-1.
func TestLatin1(t *testing.T) {
latin1 := []byte{0xc4, 'u', 0xdf, 'e', 'r', 'u', 'n', 'g', 0}
utf8 := "Äußerung"
z := Reader{r: bufio.NewReader(bytes.NewReader(latin1))}
s, err := z.readString()
if err != nil {
t.Fatalf("readString: %v", err)
}
if s != utf8 {
t.Fatalf("read latin-1: got %q, want %q", s, utf8)
}
buf := bytes.NewBuffer(make([]byte, 0, len(latin1)))
c := Writer{w: buf}
if err = c.writeString(utf8); err != nil {
t.Fatalf("writeString: %v", err)
}
s = buf.String()
if s != string(latin1) {
t.Fatalf("write utf-8: got %q, want %q", s, string(latin1))
}
}
// TestLatin1RoundTrip tests that metadata that is representable in Latin-1
// survives a round trip.
func TestLatin1RoundTrip(t *testing.T) {
testCases := []struct {
name string
ok bool
}{
{"", true},
{"ASCII is OK", true},
{"unless it contains a NUL\x00", false},
{"no matter where \x00 occurs", false},
{"\x00\x00\x00", false},
{"Látin-1 also passes (U+00E1)", true},
{"but LĀtin Extended-A (U+0100) does not", false},
{"neither does 日本語", false},
{"invalid UTF-8 also \xffails", false},
{"\x00 as does Látin-1 with NUL", false},
}
for _, tc := range testCases {
buf := new(bytes.Buffer)
w := NewWriter(buf)
w.Name = tc.name
err := w.Close()
if (err == nil) != tc.ok {
t.Errorf("Writer.Close: name = %q, err = %v", tc.name, err)
continue
}
if !tc.ok {
continue
}
r, err := NewReader(buf)
if err != nil {
t.Errorf("NewReader: %v", err)
continue
}
_, err = io.ReadAll(r)
if err != nil {
t.Errorf("ReadAll: %v", err)
continue
}
if r.Name != tc.name {
t.Errorf("name is %q, want %q", r.Name, tc.name)
continue
}
if err := r.Close(); err != nil {
t.Errorf("Reader.Close: %v", err)
continue
}
}
}
func TestWriterFlush(t *testing.T) {
buf := new(bytes.Buffer)
w := NewWriter(buf)
w.Comment = "comment"
w.Extra = []byte("extra")
w.ModTime = time.Unix(1e8, 0)
w.Name = "name"
n0 := buf.Len()
if n0 != 0 {
t.Fatalf("buffer size = %d before writes; want 0", n0)
}
if err := w.Flush(); err != nil {
t.Fatal(err)
}
n1 := buf.Len()
if n1 == 0 {
t.Fatal("no data after first flush")
}
w.Write([]byte("x"))
n2 := buf.Len()
if n1 != n2 {
t.Fatalf("after writing a single byte, size changed from %d to %d; want no change", n1, n2)
}
if err := w.Flush(); err != nil {
t.Fatal(err)
}
n3 := buf.Len()
if n2 == n3 {
t.Fatal("Flush didn't flush any data")
}
}
// Multiple gzip files concatenated form a valid gzip file.
func TestConcat(t *testing.T) {
var buf bytes.Buffer
w := NewWriter(&buf)
w.Write([]byte("hello "))
w.Close()
w = NewWriter(&buf)
w.Write([]byte("world\n"))
w.Close()
r, err := NewReader(&buf)
if err != nil {
t.Fatal(err)
}
data, err := io.ReadAll(r)
if string(data) != "hello world\n" || err != nil {
t.Fatalf("ReadAll = %q, %v, want %q, nil", data, err, "hello world")
}
}
func TestWriterReset(t *testing.T) {
buf := new(bytes.Buffer)
buf2 := new(bytes.Buffer)
z := NewWriter(buf)
msg := []byte("hello world")
z.Write(msg)
z.Close()
z.Reset(buf2)
z.Write(msg)
z.Close()
if buf.String() != buf2.String() {
t.Errorf("buf2 %q != original buf of %q", buf2.String(), buf.String())
}
}
type limitedWriter struct {
N int
}
func (l *limitedWriter) Write(p []byte) (n int, err error) {
if n := l.N; n < len(p) {
l.N = 0
return n, io.ErrShortWrite
}
l.N -= len(p)
return len(p), nil
}
// Write should never return more bytes than the input slice.
func TestLimitedWrite(t *testing.T) {
msg := []byte("a")
for lim := 2; lim < 20; lim++ {
z := NewWriter(&limitedWriter{lim})
if n, _ := z.Write(msg); n > len(msg) {
t.Errorf("Write() = %d, want %d or less", n, len(msg))
}
z.Reset(&limitedWriter{lim})
z.Header = Header{
Comment: "comment",
Extra: []byte("extra"),
ModTime: time.Now(),
Name: "name",
OS: 1,
}
if n, _ := z.Write(msg); n > len(msg) {
t.Errorf("Write() = %d, want %d or less", n, len(msg))
}
}
}