@Test  // XOR OP
public void testXOR_1() {

    VM vm = new VM();
    program =  new Program(Hex.decode("60FF60FF12"), invoke);
    String expected = "0000000000000000000000000000000000000000000000000000000000000000";
    vm.step(program);
    vm.step(program);
    vm.step(program);
    assertEquals(expected, Hex.toHexString(program.stack.peek().getData()).toUpperCase()  );
}