After you have found a profitable trading system that you already back-tested, how can you be sure that this system will produce the same gains in future?
Nobody can predict the future, your system can easily make losses in next years or can be no tradable.
There are some tests you must do before accepting a trading system, these tests swill show the robustness of your system and when passing these tests, it will be more likely to show gain in future.
Test 1 : Make sure that you put liquidity rule, that your entry and exit prices are realizable.
Test 2: Examine again your trading systems and your rules (This is very important).
I made dozen of trading systems that showed great results but after more examination, it showed that i cannot follow them in real life.
Check if there is one stock that made very big gain, the system will maybe become no profitable without this stock.
Test 3: Change twice or 3 times the date of begin for the simulation, if it still show good results then it has passed the test 3.
Test 4: Change values of some parameters or variables you have in your trading system rules, you must change one value and...