code: @Test public void test(){
    QRCode qrCode=new QRCode();
    qrCode.setMode(Mode.BYTE);
    qrCode.setECLevel(ErrorCorrectionLevel.H);
    qrCode.setVersion(Version.getVersionForNumber(7));
    qrCode.setMaskPattern(3);
    assertSame(Mode.BYTE,qrCode.getMode());
    assertSame(ErrorCorrectionLevel.H,qrCode.getECLevel());
    assertEquals(7,qrCode.getVersion().getVersionNumber());
    assertEquals(3,qrCode.getMaskPattern());
    ByteMatrix matrix=new ByteMatrix(45,45);
    for (int y=0; y < 45; ++y) {
      for (int x=0; x < 45; ++x) {
        matrix.set(x,y,(y + x) % 2);
      }
    }
    qrCode.setMatrix(matrix);
    assertSame(matrix,qrCode.getMatrix());
  }
  