I'm glad you asked
I started by downloading free data from different sources in the web. Mostly hourly / daily timeframes and backtested against it. Having done that, I connected the bot to the API of my broker and the results were far away from the good results I had in the backtest. Strange.
I started to deep dive and figured out, that my broker had quite different data on the same day as the data from other sources. I should mention here, that my bots trade CFD - not really the futures on CBOT, EUREX and so on. So market prices and especially prices outside the cash market are for every CFD broker different. I contacted the support of my broker and asked for tick data - which I received. Then I did the whole backtesting procedure once again and YES - I also had to adapt my code to this new circumstances - especially I had to modify the exit strategy rules. Because very often you have spikes (up / down) outside cash marked which would kill your stops. Sometimes I had the feeling that my broker ran his own AI bot to hunt the stops of their clients ;-) Item.
Done that, I ran the bots on the DEMO account for several month. I found some bugs, fixed them, put them again on the DEMO account and so on - until I had nothing more to fix.
After a certain time I decided that the REAL test is to run the bots on a LIVE CFD account. So I funded the live account with some hundred euros - just enough to run bots trading the low margin instruments - yes, and thats the current state.