| // 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) |
| } |
| } |
| } |