Function TestNewReaderMismatch

zstd/decoder_test.go:33–140

(t *testing.T)

)

func TestNewReaderMismatch(t *testing.T) {
	// To identify a potential decoding error, do the following steps:
	// 1) Place the compressed file in testdata, eg 'testdata/backup.bin.zst'
	// 2) Decompress the file to using zstd, so it will be named 'testdata/backup.bin'
	// 3) Run the test. A hash file will be generated 'testdata/backup.bin.hash'
	// 4) The decoder will also run and decode the file. It will stop as soon as a mismatch is found.
	// The hash file will be reused between runs if present.
	const baseFile = "testdata/backup.bin"
	const blockSize = 1024
	hashes, err := os.ReadFile(baseFile + ".hash")
	if os.IsNotExist(err) {
		// Create the hash file.
		f, err := os.Open(baseFile)
		if os.IsNotExist(err) {
			t.Skip("no decompressed file found")
			return
		}
		defer f.Close()
		br := bufio.NewReader(f)
		var tmp [8]byte
		xx := xxhash.New()
		for {
			xx.Reset()
			buf := make([]byte, blockSize)
			n, err := io.ReadFull(br, buf)
			if err != nil {
				if err != io.EOF && err != io.ErrUnexpectedEOF {
					t.Fatal(err)
				}
			}
			if n > 0 {
				_, _ = xx.Write(buf[:n])
				binary.LittleEndian.PutUint64(tmp[:], xx.Sum64())
				hashes = append(hashes, tmp[4:]...)
			}
			if n != blockSize {
				break
			}
		}
		err = os.WriteFile(baseFile+".hash", hashes, os.ModePerm)
		if err != nil {
			// We can continue for now
			t.Error(err)
		}
		t.Log("Saved", len(hashes)/4, "hashes as", baseFile+".hash")
	}

	f, err := os.Open(baseFile + ".zst")
	if os.IsNotExist(err) {
		t.Skip("no compressed file found")
		return
	}
	defer f.Close()
	dec, err := NewReader(f, WithDecoderConcurrency(1))
	if err != nil {
		t.Fatal(err)
	}
	defer dec.Close()