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// Copyright 2009 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 zlib
import (
"io"
"io/ioutil"
"os"
"testing"
)
var filenames = []string{
"../testdata/e.txt",
"../testdata/pi.txt",
}
// Tests that compressing and then decompressing the given file at the given compression level
// yields equivalent bytes to the original file.
func testFileLevel(t *testing.T, fn string, level int) {
// Read the file, as golden output.
golden, err := os.Open(fn, os.O_RDONLY, 0444)
if err != nil {
t.Errorf("%s (level=%d): %v", fn, level, err)
return
}
defer golden.Close()
// Read the file again, and push it through a pipe that compresses at the write end, and decompresses at the read end.
raw, err := os.Open(fn, os.O_RDONLY, 0444)
if err != nil {
t.Errorf("%s (level=%d): %v", fn, level, err)
return
}
piper, pipew := io.Pipe()
defer piper.Close()
go func() {
defer raw.Close()
defer pipew.Close()
zlibw, err := NewWriterLevel(pipew, level)
if err != nil {
t.Errorf("%s (level=%d): %v", fn, level, err)
return
}
defer zlibw.Close()
var b [1024]byte
for {
n, err0 := raw.Read(b[0:])
if err0 != nil && err0 != os.EOF {
t.Errorf("%s (level=%d): %v", fn, level, err0)
return
}
_, err1 := zlibw.Write(b[0:n])
if err1 == os.EPIPE {
// Fail, but do not report the error, as some other (presumably reportable) error broke the pipe.
return
}
if err1 != nil {
t.Errorf("%s (level=%d): %v", fn, level, err1)
return
}
if err0 == os.EOF {
break
}
}
}()
zlibr, err := NewReader(piper)
if err != nil {
t.Errorf("%s (level=%d): %v", fn, level, err)
return
}
defer zlibr.Close()
// Compare the two.
b0, err0 := ioutil.ReadAll(golden)
b1, err1 := ioutil.ReadAll(zlibr)
if err0 != nil {
t.Errorf("%s (level=%d): %v", fn, level, err0)
return
}
if err1 != nil {
t.Errorf("%s (level=%d): %v", fn, level, err1)
return
}
if len(b0) != len(b1) {
t.Errorf("%s (level=%d): length mismatch %d versus %d", fn, level, len(b0), len(b1))
return
}
for i := 0; i < len(b0); i++ {
if b0[i] != b1[i] {
t.Errorf("%s (level=%d): mismatch at %d, 0x%02x versus 0x%02x\n", fn, level, i, b0[i], b1[i])
return
}
}
}
func TestWriter(t *testing.T) {
for _, fn := range filenames {
testFileLevel(t, fn, DefaultCompression)
testFileLevel(t, fn, NoCompression)
for level := BestSpeed; level <= BestCompression; level++ {
testFileLevel(t, fn, level)
}
}
}
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