First you may use back testing. The last half a year or whatever period you select. This doesn’t take too long because you can rapidly scroll through historical charts searching for the signals that would have led you to make a trade if you had been operating your system live at that time.
Back testing should give you an idea of whether a system has potential. Naturally the market isn’t going to copy in exactly the same way so you should take into account the proven fact that you could have struck lucky or unfortunate and picked a point in time when the system performed abnormally well or badly. For this reason, it is best to back test over the longest possible time and maybe split your tests so that instead of testing, for instance, one entire year when the market might have been especially powerful or feeble, take the 1st quarter of year one, quarter two of year two, etc so that you test one 3-month period from every year of four years. Here you are dealing with the live market but n