slice := make([]byte, 0)
	n, err := b.Read(slice)
	if err != nil {
		t.Errorf("read error: %v", err)
	}
	if n != 0 {
		t.Errorf("wrong count; got %d want 0", n)
	}
}

func TestUnreadByte(t *testing.T) {
	b := new(Buffer)

	// check at EOF
	if err := b.UnreadByte(); err == nil {
		t.Fatal("UnreadByte at EOF: got no error")
	}
	if _, err := b.ReadByte(); err == nil {

	br := NewReader(strings.NewReader("example"))
	br.WriteTo(io.Discard)
	if err := br.UnreadByte(); err == nil {
		t.Error("UnreadByte didn't fail after WriteTo")
	}
}

func TestUnreadByte(t *testing.T) {
	segments := []string{"Hello, ", "world"}
	r := NewReader(&StringReader{data: segments})
	got := ""
	want := strings.Join(segments, "")
	// Normal execution.
	for {
		b1, err := r.ReadByte()