@Test // SUB OP
public void testSUB_1() {

    VM vm = new VM();
    program =  new Program(Hex.decode("6004600603"), invoke);
    String s_expected_1 = "0000000000000000000000000000000000000000000000000000000000000002";
    vm.step(program);
    vm.step(program);
    vm.step(program);
    DataWord item1 = program.stackPop();
    assertEquals(s_expected_1, Hex.toHexString(item1.getData()).toUpperCase());
}