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|
package bitstream
import (
"bytes"
"fmt"
"io"
"strings"
"testing"
)
func TestBitStreamEOF(t *testing.T) {
br := NewReader(strings.NewReader("0"))
b, err := br.ReadByte()
if b != '0' {
t.Error("ReadByte didn't return first byte")
}
b, err = br.ReadByte()
if err != io.EOF {
t.Error("ReadByte on empty string didn't return EOF")
}
// 0 = 0b00110000
br = NewReader(strings.NewReader("0"))
buf := bytes.NewBuffer(nil)
bw := NewWriter(buf)
for i := 0; i < 4; i++ {
bit, err := br.ReadBit()
if err == io.EOF {
break
}
if err != nil {
t.Error("GetBit returned error err=", err.Error())
return
}
err = bw.WriteBit(bit)
if err != nil {
t.Errorf("unexpected writer error")
}
}
bw.Flush(One)
err = bw.WriteByte(0xAA)
if err != nil {
t.Error("unable to WriteByte")
}
c := buf.Bytes()
if len(c) != 2 || c[1] != 0xAA || c[0] != 0x3f {
t.Error("bad return from 4 read bytes")
}
_, err = NewReader(strings.NewReader("")).ReadBit()
if err != io.EOF {
t.Error("ReadBit on empty string didn't return EOF")
}
}
// reader that returns a single byte with EOF
type eofReader struct {
readCalled bool
}
func (e *eofReader) Read(p []byte) (int, error) {
if e.readCalled {
return 0, io.EOF
}
e.readCalled = true
p[0] = 'A'
return 1, io.EOF
}
func TestBitStreamReadEOF(t *testing.T) {
br := NewReader(&eofReader{})
r, _ := br.ReadBits(8)
if r != 'A' {
t.Errorf("failed to read single byte with EOF: %08b", r)
}
}
func TestBitStream(t *testing.T) {
buf := bytes.NewBuffer(nil)
br := NewReader(strings.NewReader("hello"))
bw := NewWriter(buf)
for {
bit, err := br.ReadBit()
if err == io.EOF {
break
}
if err != nil {
t.Error("GetBit returned error err=", err.Error())
return
}
err = bw.WriteBit(bit)
if err != nil {
t.Errorf("unexpected writer error")
}
}
s := buf.String()
if s != "hello" {
t.Error("expected 'hello', got=", []byte(s))
}
}
func TestByteStream(t *testing.T) {
buf := bytes.NewBuffer(nil)
br := NewReader(strings.NewReader("hello"))
bw := NewWriter(buf)
for i := 0; i < 3; i++ {
bit, err := br.ReadBit()
if err == io.EOF {
break
}
if err != nil {
t.Error("GetBit returned error err=", err.Error())
return
}
err = bw.WriteBit(bit)
if err != nil {
t.Errorf("unexpected writer error")
}
}
for i := 0; i < 3; i++ {
byt, err := br.ReadByte()
if err == io.EOF {
break
}
if err != nil {
t.Error("GetByte returned error err=", err.Error())
return
}
bw.WriteByte(byt)
}
u, err := br.ReadBits(13)
if err != nil {
t.Error("ReadBits returned error err=", err.Error())
return
}
err = bw.WriteBits(u, 13)
if err != nil {
t.Errorf("unexpected writer error")
}
err = bw.WriteBits(('!'<<12)|('.'<<4)|0x02, 20)
if err != nil {
t.Errorf("unexpected writer error")
}
// 0x2f == '/'
bw.Flush(One)
s := buf.String()
if s != "hello!./" {
t.Errorf("expected 'hello!./', got=%x", []byte(s))
}
}
var myError error = fmt.Errorf("my error")
type badWriter struct{}
func (w *badWriter) Write(p []byte) (n int, err error) {
return 0, myError
}
func TestErrorPropagation(t *testing.T) {
// check WriteBit
w := &badWriter{}
bw := NewWriter(w)
for i := 0; i < 7; i++ {
err := bw.WriteBit(One)
if err != nil {
t.Errorf("unexpected error during buffered write operation")
}
}
err := bw.WriteBit(One)
if err != myError {
t.Errorf("failed to propagate error")
}
// check WriteBits
w = &badWriter{}
bw = NewWriter(w)
err = bw.WriteBits(256, 8)
if err != myError {
t.Errorf("failed to propagate error")
}
}
func TestReset(t *testing.T) {
r := NewReader(strings.NewReader("abc"))
b, _ := r.ReadBits(8)
if b != 'a' {
t.Errorf("expected 'a', got=%08b", b)
}
r.Reset(strings.NewReader("def"))
b, _ = r.ReadBits(8)
if b != 'd' {
t.Errorf("expected 'd', got=%08b", b)
}
firstWriter := bytes.NewBuffer(nil)
w := NewWriter(firstWriter)
w.WriteBits(97, 8)
secondWriter := bytes.NewBuffer(nil)
w.Reset(secondWriter)
w.WriteBits(98, 8)
if firstWriter.String() != "a" {
t.Errorf("expected 'a', got=%x", firstWriter.Bytes())
}
if secondWriter.String() != "b" {
t.Errorf("expected 'b', got=%x", secondWriter.Bytes())
}
}
|
