func TestWriterReturnValues(t *testing.T) {
	w := NewWriter(io.Discard, LSB, 8)
	n, err := w.Write([]byte("asdf"))
	if n != 4 || err != nil {
		t.Errorf("got %d, %v, want 4, nil", n, err)
	}
}

func TestSmallLitWidth(t *testing.T) {
	w := NewWriter(io.Discard, LSB, 2)
	if _, err := w.Write([]byte{0x03}); err != nil {
		t.Fatalf("write a byte < 1<<2: %v", err)
	}
	if _, err := w.Write([]byte{0x04}); err == nil {